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New in spot 2.7 (2018-12-11)
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  Command-line tools:

  - ltlsynt now has three algorithms for synthesis:
    --algo=sd     is the historical one. The automaton of the formula
                  is split to separate inputs and outputs, then
                  determinized (with Safra construction).
    --algo=ds     the automaton of the formula is determinized (Safra),
                  then split to separate inputs and outputs.
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    --algo=lar    translate the formula to a deterministic automaton
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                  with an arbitrary acceptance condition, then turn it
                  into a parity automaton using LAR, and split it.
    In all three cases, the obtained parity game is solved using
    Zielonka algorithm. Calude's quasi-polynomial time algorithm has
    been dropped as it was not used.

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  - ltlfilt learned --liveness to match formulas representing liveness
    properties.
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  - the --stats= option of tools producing automata learned how to
    tell if an automaton uses universal branching (%u), or more
    precisely how many states (%[s]u) or edges (%[e]u) use universal
    branching.

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  Python:

  - spot.translate() and spot.postprocess() now take an xargs=
    argument similar to the -x option of ltl2tgba and autfilt, making
    it easier to fine tune these operations.  For instance
        ltl2tgba 'GF(a <-> XXa)' --det -x gf-guarantee=0
    would be written in Python as
        spot.translate('GF(a <-> XXa)', 'det', xargs='gf-guarantee=0')
    (Note: those extra options are documented in the spot-x(7) man page.)

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  - spot.is_generalized_rabin() and spot.is_generalized_streett() now return
    a tuple (b, v) where b is a Boolean, and v is the vector of the sizes
    of each generalized pair.  This is a backward incompatible change.

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  Library:

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  - The LTL parser learned syntactic sugar for nested ranges of X
    using the X[n], F[n:m], and G[n:m] syntax of TSLF.  (These
    correspond to the next!, next_e!, and next_a! operators of PSL,
    but we do not support those under these names currently.)

      X[6]a = XXXXXXa
      F[2:4]a = XX(a | X(a | Xa))
      G[2:4]a = XX(a & X(a & Xa))

    The corresponding constructors (for C++ and Python) are
      formula::X(unsigned, formula)
      formula::F(unsigned, unsigned, formula)
      formula::G(unsigned, unsigned, formula)
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  - spot::unabbreviate(), used to rewrite away operators such as M or
    W, learned to use some shorter rewritings when an argument (e) is
    a pure eventuality or (u) is purely universal:

      Fe = e
      Gu = u
      f R u = u
      f M e = F(f & e)
      f W u = G(f | u)

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  - The twa_graph class has a new dump_storage_as_dot() method
    to show its data structure.  This is more conveniently used
    as aut.show_storage() in a Jupyter notebook.  See
    https://spot.lrde.epita.fr/ipynb/twagraph-internals.html

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  - spot::generic_emptiness_check() is a new function that performs
    emptiness checks of twa_graph_ptr (i.e., automata not built
    on-the-fly) with an *arbitrary* acceptance condition.  Its sister
    spot::generic_emptiness_check_scc() can be used to decide the
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    emptiness of an SCC.  This is now used by
    twa_graph_ptr::is_empty(), twa_graph_ptr::intersects(), and
    scc_info::determine_unknown_acceptance().
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  - The new function spot::to_parity() translates an automaton with
    arbitrary acceptance condition into a parity automaton, based on a
    last-appearance record (LAR) construction.  (It is used by ltlsynt
    but not yet by autfilt or ltl2tgba.)
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  - The new function is_liveness() and is_liveness_automaton() can be
    used to check whether a formula or an automaton represents a
    liveness property.

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  - Two new functions count_univbranch_states() and
    count_univbranch_edges() can help measuring the amount of
    universal branching in alternating automata.

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  Bugs fixed:

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  - translate() would incorrectly mark as stutter-invariant
    some automata produced from formulas of the form X(f...)
    where f... is syntactically stutter-invariant.

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  - acc_cond::is_generalized_rabin() and
    acc_cond::is_generalized_streett() did not recognize the cases
    were a single generalized pair is used.

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  - The pair of acc_cond::mark_t returned by
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    acc_code::used_inf_fin_sets(), and the pair (bool,
    vector_rs_pairs) by acc_cond::is_rabin_like() and
    acc_cond::is_streett_like() were not usable in Python.
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  - Many object types had __repr__() methods that would return the
    same string as __str__(), contrary to Python usage where repr(x)
    should try to show how to rebuild x.  The following types have
    been changed to follow this convention:
       spot.acc_code
       spot.acc_cond
       spot.atomic_prop_set
       spot.formula
       spot.mark_t
       spot.twa_run (__repr__ shows type and address)
       spot.twa_word (likewise, but _repr_latex_ used in notebooks)

    Note that this you were relying on the fact that Jupyter calls
    repr() to display returned values, you may want to call print()
    explicitely if you prefer the old representation.

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  - Fix compilation under Cygwin and Alpine Linux, both choking
    on undefined secure_getenv().

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New in spot 2.6.3 (2018-10-17)
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  Bugs fixed:

  - Running "ltl2tgba -B" on formulas of the type FG(safety) would
    unexpectedly use a co-Büchi automaton as an intermediate step.
    This in turn caused "ltl2tgba -U -B" to not produce unambiguous
    automata.

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  - ltl2tgba --low now disables the "gf-guarantee" feature, as
    documented.

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  - ltlfilt's --accept-word and --reject-word options were ignored
    unless used together.

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New in spot 2.6.2 (2018-09-28)
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  Build:

  - We no longer distribute the Python-based CGI script + javascript
    code for the online translator.  Its replacement has its own
    repository: https://gitlab.lrde.epita.fr/spot/spot-web-app/
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  Library:

  - When states are highlighted with more than 8 colors, print_dot()
    will add some extra markers to help distinguishing the colors.
    This helps with the fact that colors 8-15 are lighter versions of
    colors 0-7, and that higher color numbers cycle into this 16-color
    palette.

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  Bugs fixed:

  - exclusive_ap::constrain() (called by autfilt --exclusive-ap=...)
    would incorrectly copy the "universal" property of the input
    automaton, causing print_hoa() to fail.

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  - configure --disable-doxygen would actually enable it.

  - Fix several warnings emited by the development version of GCC.

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New in spot 2.6.1  (2018-08-04)
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  Command-line tools:

  - "ltlfilt --suspendable" is now a synonym for
    "ltlfilt --universal --eventual".
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  Bugs fixed:

  - scc_info::split_on_sets() did not correctly register the
    atomic propositions of the returned automata.

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  - The spot::tl_simplifier class could raise an exception while
    attempting to reduce formulas containing unsimplified <->, -> or
    xor, if options nenoform_stop_on_boolean and synt_impl are both
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    set.  (This combination of options is not available from
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    command-line tools.)

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  - The spot::contains(a, b) function introduced in 2.6 was testing
    a⊆b instead of a⊇b as one would expect.  Infortunately the
    documentation was also matching the code, so this is a backward
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    incompatible change, but a short-lived one.
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  - The Python binding of the getter of spot::parsed_formula::f was
    returning a reference instead of a copy, causing issues if the
    reference outlasted the parsed_formula struct.

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New in spot 2.6  (2018-07-04)
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  Command-line tools:

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  - autfilt learned --is-colored to filter automata that use
    exactly one acceptance set per mark or transition.

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  - autfilt learned --has-univ-branching and --has-exist-branching
    to keep automata that have universal branching, or that make
    non-deterministic choices.

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  - autcross' tool specifications now have %M replaced by the name of
    the input automaton.

  - autcross now aborts if there is any parser diagnostic for the
    input automata (previous versions would use the input automaton
    whenever the parser would manage to read something).

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  - ltlcross, ltldo, and autcross learned shorthands to call
    delag, ltl2dra, ltl2dgra, and nba2dpa.

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  - When autfilt is asked to build a Büchi automaton from
    of a chain of many products, as in
    "autfilt -B --product 1.hoa ... --product n.hoa in.hoa"
    then it will automatically degeneralize the intermediate
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    products to avoid exceeding the number of supported
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    acceptance sets.

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  - genltl learned to generate six new families of LTL formulas:
      --gf-equiv-xn=RANGE    GF(a <-> X^n(a))
      --gf-implies-xn=RANGE  GF(a -> X^n(a))
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      --sejk-f=RANGE[,RANGE] f(0,j)=(GFa0 U X^j(b)), f(i,j)=(GFai U
                             G(f(i-1,j)))
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      --sejk-j=RANGE         (GFa1&...&GFan) -> (GFb1&...&GFbn)
      --sejk-k=RANGE         (GFa1|FGb1)&...&(GFan|FGbn)
      --sejk-patterns[=RANGE]   φ₁,φ₂,φ₃ from Sikert et al's [CAV'16]
                             paper (range should be included in 1..3)

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  - genltl --ms-example can now take a two-range argument,
    (as --sejk-f above).

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  Build:

  - ./configure --enable-max-accsets=N let you specify a maximum
    number of acceptance sets that Spot should support.  The default
    is still 32, but this limit is no longer hardcoded.  Larger values
    will cost additional memory and time.

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  - We know distribute RPM packages for Fedora 28.  See
    file:///home/adl/git/spot/doc/userdoc/install.html#Fedora

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  Library:

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  - The PSL/LTL simplification routine learned the following:

      q R Xf = X(q R f)  if q is suspendable
      q U Xf = X(q U f)  if q is suspendable
      {SERE;1} = {1}     if {SERE} accepts [*0]
      {SERE;1} = {SERE}  if {SERE} does not accept [*0]

  - gf_guarantee_to_ba() is a specialized construction for translating
    formulas of the form GF(guarantee) to BA or DBA, and
    fg_safety_to_dca() is a specialized construction for translating
    formulas of the form FG(safety) to DCA.  These are generalizations
    of some constructions proposed by J. Esparza, J. Křentínský, and
    S. Sickert (LICS'18).

    These are now used by the main translation routine, and can be
    disabled by passing -x '!gf-guarantee' to ltl2tgba.  For example,
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    here are the size of deterministic transition-based generalized
    Büchi automata constructed from four GF(guarantee) formulas with
    two versions of Spot, and converted to other types of
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    deterministic automata by other tools distributed with Owl 18.06.
    "x(y)" means x states and y acceptance sets.
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                               ltl2tgba -D  delag ltl2dra
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                                2.5   2.6   18.06  18.06
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    -------------------------  -----------  -------------
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    GF(a <-> XXa)               9(1)  4(1)   4(2)   9(4)
    GF(a <-> XXXa)             27(1)  8(1)   8(2)  25(4)
    GF(((a & Xb) | XXc) & Xd)   6(1)  4(1)  16(1)   5(2)
    GF((b | Fa) & (b R Xb))     6(2)  2(1)   3(4)   3(4)

    Note that in the above the automata produced by 'ltl2tgba -D' in
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    version 2.5 were not deterministic (because -D is only a
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    preference).  They are deterministic in 2.6 and other tools.
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  - spot::product() and spot::product_or() learned to produce an
    automaton with a simpler acceptance condition if one of the
    argument is a weak automaton.  In this case the resulting
    acceptance condition is (usually) that of the other argument.

  - spot::product_susp() and spot::product_or_susp() are new
    functions for building products between an automaton A and
    a "suspendable" automaton B.  They are also optimized for
    the case that A is weak.

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  - When 'generic' acceptance is enabled, the translation routine will
    split the input formula on Boolean operators into components that
    are syntactically 'obligation', 'suspendable', or 'something
    else'.  Those will be translated separately and combined with
    product()/product_susp().  This is inspired by the ways things are
    done in ltl2dstar or delag, and can be disabled by passing option
    -xltl-split=0, as in ltl2tgba -G -D -xltl-split=0.  Here are the
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    sizes of deterministic automata (except for ltl3tela which produces
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    non-deterministic automata) produced with generic acceptance
    using two versions of ltl2tgba and other tools for reference.

                                             ltl2tgba -DG  delag  ltl3tela
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                                              2.5    2.6   18.06    1.1.2
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                                             ------------ ------- --------
    FGa0&GFb0                                 2(2)   1(2)   1(2)    1(2)
    (FGa1&GFb1)|FGa0|GFb0                    16(6)   1(4)   1(4)    1(9)
    (FGa2&GFb2)|((FGa1|GFb1)&FGa0&GFb0)      29(8)   1(6)   1(6)    3(11)
    FGa0|GFb0                                 5(4)   1(2)   1(2)    1(5)
    (FGa1|GFb1)&FGa0&GFb0                     8(4)   1(4)   1(4)    1(7)
    (FGa2|GFb2)&((FGa1&GFb1)|FGa0|GFb0)     497(14)  1(6)   1(6)    1(14)
    GFa1 <-> GFz                              4(6)   1(3)   1(4)    1(7)
    (GFa1 & GFa2) <-> GFz                     8(4)   1(3)   1(6)    3(10)
    (GFa1 & GFa2 & GFa3) <-> GFz             21(4)   1(4)   1(8)    3(13)
    GFa1 -> GFz                               5(4)   1(2)   1(2)    1(5)
    (GFa1 & GFa2) -> GFz                     12(4)   1(3)   1(3)    1(6)
    (GFa1 & GFa2 & GFa3) -> GFz              41(4)   1(4)   1(4)    1(7)
    FG(a|b)|FG(!a|Xb)                         4(2)   2(2)   2(2)    2(3)
    FG(a|b)|FG(!a|Xb)|FG(a|XXb)              21(2)   4(3)   4(3)    4(4)
    FG(a|b)|FG(!a|Xb)|FG(a|XXb)|FG(!a|XXXb) 170(2)   8(4)   8(4)    8(5)

  - For 'parity' output, the 'ltl-split' optimization just separates
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    obligation subformulas from the rest, where a determinization is
    still performed.
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                                 ltl2tgba -DP  ltl3dra  ltl2dpa
                                   2.5   2.6    0.2.3    18.06
                                -------------- -------  -------
    FGp0 & (Gp1 | XFp2)           6(2)  4(1)     4(1)     4(2)
    G!p0 | F(p0 & (!p1 W p2))     5(2)  4(2)     n/a      5(2)
    (p0 W XXGp0) & GFp1 & FGp2    6(2)  5(2)     n/a      6(3)
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    (The above just show a few cases that were improved.  There are
    many cases where ltl2dpa still produces smaller automata.)

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  - The automaton postprocessor will now simplify acceptance
    conditions more aggressively, calling spot::simplify_acceptance()
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    or spot::cleanup_acceptance() depending on the optimization level.
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  - print_dot(), used to print automata in GraphViz's format,
    underwent several changes:
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    * option "a", for printing the acceptance condition, is now
      enabled by default.  Option "A", introduced in Spot 2.4, can be
      used to hide the acceptance condition in case you do not want
      it.  This change of course affects the --dot option of all the
      command-line tools, as well as the various way to display
      automata using the Python bindings.

    * when option "1" is used to hide state names and force the
      display of state numbers, the actual state names is now moved to
      the "tooltip" field of the state.  The SVG files produced by
      "dot -Tsvg" will show those as popups.  This is also done for
      state labels of Kripke structures.

    * the output digraph is now named using the name of the automaton
      if available, or the empty string otherwise.  (Previous versions
      used to call all digraphs "G".)  This name appears as a tooltip
      in SVG figures when the mouse is over the acceptance condition.

    * a new option "u" hides "true states" behind "exiting
      transitions".  This can be used to display alternating automata
      in a way many people expect.

    * a new option "K" cancels the effect of "k" (which uses state
      labels whenever possible).  This is most useful when one want to
      force transition-labeling of a Kripke structure, where "k" is
      usually the default.

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  - spot::twa_graph::merge_states() is a new method that merges states
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    with the exact same outgoing edges. As it performs no reordering
    of the edges, it is better to call it when you know that the edges
    in the twa_graph are sorted (e.g. after a call to merge_edges()).
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  - spot::twa_graph::purge_unreachable_states() now takes a function
    which is called with the new numbering of states. This is useful
    to update an external structure that references states of the twa
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    that we want to purge.

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  - spot::scc_filter() now automatically turns automata marked as
    inherently-weak into weak automata with state-based acceptance.
    The acceptance condition is set to Büchi unless the input had
    co-Büchi or t acceptance.  spot::scc_filter_states() will pass
    inherently-weak automata to spot::scc_filter().

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  - spot::cleanup_parity() and spot::cleanup_parity_here() are smarter
    and now remove from the acceptance condition the parity colors
    that are not used in the automaton.
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  - spot::contains() and spot::are_equivalent() can be used to
    check language containement between two automata or formulas.
    They are most welcome in Python, since we used to redefine
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    them every now and them.  Some examples are shown in
    https://spot.lrde.epita.fr/ipynb/contains.html

  - aut1->exclusive_word(aut2) is a new method that returns a word
    accepted by aut1 or aut2 but not both.  The exclusive_run()
    variant will return.  This is useful when comparing automata and
    looking for differences.  See also
    https://spot.lrde.epita.fr/ipynb/contains.html
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  - spot::complement_semidet(aut) is a new function that returns the
    complement of aut, where aut is a semideterministic automaton. The
    function uses the NCSB complementation algorithm proposed by
    F. Blahoudek, M. Heizmann, S. Schewe, J. Strejček, and MH. Tsai
    (TACAS'16).

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  - spot::remove_alternation() was slightly improved on very-weak
    alternating automata: the labeling of the outgoing transitions in
    the resulting TGBA makes it more likely that simulation-based
    reductions will reduce it.

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  - When applied to automata that are not WDBA-realizable,
    spot::minimize_wdba() was changed to produce an automaton
    recognizing a language that includes the original one.  As a
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    consequence spot::minimize_obligation() and
    spot::is_wdba_realizable() now only need one containement check
    instead of two.
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  - Slightly improved log output for the SAT-based minimization
    functions.  The CSV log files now include an additional column
    with the size of the reference automaton, and they now have a
    header line.  These log files give more details and are more
    accurate in the case of incremental SAT-solving.
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  Python:

  - New spot.jupyter package.  This currently contains a function for
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    displaying several arguments side by side in a Jupyter notebook.
    See https://spot.lrde.epita.fr/ipynb/alternation.html for some
    examples.
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  - Strings are now implicitely converted into formulas when passed
    as arguments to functions that expect formulas.  Previously this
    was done only for a few functions.

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  - The Python bindings for sat_minimize() now have display_log and
    return_log options; these are demonstrated on the new
    https://spot.lrde.epita.fr/ipynb/satmin.html page.

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  Bugs fixed:

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  - Python *.py and *.so files are now always installed into the same
    directory.  This was an issue on systems like Fedora that separate
    plateform-specific packages from non-plateform-specific ones.

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  - print_dot() will correctly escape strings containing \n in HTML
    mode.

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  - The HOA parser will now accept Alias: declarations that occur
    before AP:.

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  - The option --allow-dups of randltl now works properly.

  - Converting generalized-co-Büchi to Streett using dnf_to_nca()
    could produce bogus automata if the input had rejecting SCCs.
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  Deprecation notices:
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  - The type spot::acc_cond::mark_t has been overhauled and uses
    a custom bit-vector to represent acceptance sets instead of
    storing everything in a "unsigned int".  This change is
    to accomodate configure's --enable-max-accsets=N option and
    has several effect:

    * The following shortcuts are deprecated:
        acc_cond::mark_t m1 = 0U;
        acc_cond::mark_t m2 = -1U;
      instead, use:
        acc_cond::mark_t m1 = {};
        acc_cond::mark_t m2 = acc_cond::mark_t::all();

    * acc_cond::mark_t::value_t is deprecated.  It is now only
      defined when --enable-max-accsets=32 (the default) and
      equal to "unsigned" for backward compatibility reasons.

  Backward incompatibilities:

  - Functions spot::parity_product() and spot::parity_product_or()
    were removed.  The code was unused, hard to maintain, and bogus.

  - The output of print_dot() now include the acceptance condition.
    Add option "A" (supported since version 2.4) to cancel that.

  - Because genltl now supports LTL pattern with two argumens, using
    --format=%L may output two comma-separated integer.  This is an
    issue if you used to produce CSV files using for instance:
      genltl --format='%F,%L,%f' ...
    Make sure to quote %L to protect the potential commas:
      genltl --format='%F,"%L",%f' ...

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  - In Spot 2.5 and prior running "ltl2tgba --generic --det" on some
    formula would attempt to translate it as deterministic TGBA or
    determinize it into an automaton with parity acceptance.  Version
    2.5 introduced --parity to force parity acceptance on the output.
    This version finally gives --generic some more natural semantics:
    any acceptance condition can be used.

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New in spot 2.5.3 (2018-04-20)
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  Bugs fixed:

  - "autfilt --cobuchi --small/--det" would turn a transition-based
    co-Büchi automaton into a state-based co-Büchi.

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  - Fix cryptic error message from Python's spot.translate() and
    spot.postprocess() when supplying conflicting arguments.

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  - "autfilt -B --sat-minimize" was incorrectly producing
    transition-based automata.

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  - Using spot.automata("cmd...|") to read just a few automata out of
    an infinite stream would not properly terminate the command.

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  - The is_unambiguous() check (rewritten in Spot 2.2) could mark some
    unambiguous automata as ambiguous.

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New in spot 2.5.2 (2018-03-25)
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  Bugs fixed:

  - acc_cond::is_generalized_rabin() and
    acc_cond::is_generalized_streett() would segfault on weird
    acceptance conditions such as "3 t" or "3 f".

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  - remove_fin() and streett_to_generalized_buchi() should never
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    return automata with "f" acceptance.

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  - "autfilt --acceptance-is=Fin-less" no longer accept automata
    with "f" acceptance.

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  - twa_run methods will now diagnose cases where the cycle is
    unexpectedly empty instead of segfaulting.

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  - spot::closure(), used by default for testing stutter-invariance,
    was using an optimization incorrect if the acceptance condition
    had some Fin(x).  Consequently stutter-invariance tests for
    automata, for instance with "autfilt --is-stutter-invariant",
    could be to be wrong (even if the input does not use Fin(x), its
    complement, used in the stutter-invariance test likely will).
    Stutter-invariance checks of LTL formulas are not affected.

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New in spot 2.5.1 (2018-02-20)
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  Library:

  - iar() and iar_maybe() now also handle Streett-like conditions.

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  Bugs fixed:

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  - iar() and iar_maybe() properly handle Rabin-like conditions.

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  - streett_to_generalized_buchi() could produce incorrect result on
    Streett-like input with acceptance like (Inf(0)|Fin(1))&Fin(1)
    where some Fin(x) is used both with and without a paired Fin(y).
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  - is_generalized_rabin() had a typo that caused some non-simplified
    acceptance conditions like Fin(0)|(Fin(0)&Inf(1)) to be
    incorrectly detecteded as generalized-Rabin 2 0 1 and then output
    as Fin(0)|(Fin(1)&Inf(2)) instead.  Likewise for
    is_generalized_streett

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  - the conversion from Rabin to Büchi was broken on Rabin-like
    acceptance condition where one pair used Fin(x) and another pair
    used Inf(x) with the same x.  Unfortunately, this situation could
    also occur as a side effect of simplifying the acceptance
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    condition (by merging identical set) of some automaton prior to
    converting it to Büchi.
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  - dnf_to_dca() was mishandling some Rabin-like input.

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New in spot 2.5 (2018-01-20)
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  Build:

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  - We no longer distribute the doxygen-generated documentation in
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    the tarball of Spot to save space.  This documentation is still
    available online at https://spot.lrde.epita.fr/doxygen/.  If you
    want to build a local copy you can configure Spot with
    --enable-doxygen, or simply run "cd doc && make doc".

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  - All the images that illustrate the documentation have been
    converted to SVG, to save space and improve quality.

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  Tools:

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  - ltlsynt is a new tool for synthesizing a controller from LTL/PSL
    specifications.

  - ltlcross learned --reference=COMMANDFMT to specify a translator
    that should be trusted.  Doing so makes it possible to reduce the
    number of tests to be performed, as all other translators will be
    compared to the reference's output when available.  Multiple
    reference can be given; in that case other tools are compared
    against the smallest reference automaton.

  - autcross, ltlcross, and ltldo learned --fail-on-timeout.

  - ltl2tgba, autfilt, and dstar2tgba have some new '--parity' and
    '--colored-parity' options to force parity acceptance on the
    output.  Different styles can be requested using for instance
    --parity='min odd' or --parity='max even'.

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  - ltl2tgba, autfilt, and dstar2tgba have some new '--cobuchi' option
    to force co-Büchi acceptance on the output.  Beware: if the input
    language is not co-Büchi realizable the output automaton will
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    recognize a superset of the input.  Currently, the output is
    always state-based.
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  - genltl learned to generate six new families of formulas, taken from
    the SYNTCOMP competition on reactive synthesis, and from from
    Müller & Sickert's GandALF'17 paper:
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    --gf-equiv=RANGE       (GFa1 & GFa2 & ... & GFan) <-> GFz
    --gf-implies=RANGE     (GFa1 & GFa2 & ... & GFan) -> GFz
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    --ms-example=RANGE     GF(a1&X(a2&X(a3&...)))&F(b1&F(b2&F(b3&...)))
    --ms-phi-h=RANGE       FG(a|b)|FG(!a|Xb)|FG(a|XXb)|FG(!a|XXXb)|...
    --ms-phi-r=RANGE       (FGa{n}&GFb{n})|((FGa{n-1}|GFb{n-1})&(...))
    --ms-phi-s=RANGE       (FGa{n}|GFb{n})&((FGa{n-1}&GFb{n-1})|(...))
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  - autfilt learned --streett-like to convert automata with DNF
    acceptance into automata with Streett-like acceptance.
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  - autfilt learned --acceptance-is=ACC to filter automata by
    acceptance condition.  ACC can be the name of some acceptance
    class (e.g. Büchi, Fin-less, Streett-like) or a precise acceptance
    formula in the HOA syntax.

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  - ltldo learned to limit the number of automata it outputs using -n.

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  - ltlfilt learned to measure wall-time using --format=%r, and
    cpu-time with --format=%R.
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  - The --format=%g option of tools that output automata used to
    print the acceptance condition as a *formula* in the HOA format.
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    This %g may now take optional arguments to print the acceptance
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    *name* in different formats.  For instance

       ... | autfilt -o '%[s]g.hoa'

    will separate a stream of automata into different files named
    by their acceptance name (Buchi, co-Buchi, Streett, etc.) or
    "other" if no name is known for the acceptance condition.

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  - Tools that produce formulas now support --format=%[OP]n to
    display the nesting depth of operator OP.

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  - The new -x tls-impl=N option allows to fine-tune the
    implication-based simplification rules of ltl2tgba.  See the
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    spot-x(7) man page for details.
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  - All tools learned to check the SPOT_OOM_ABORT environment
    variable.  This is only useful for debuging out-of-memory
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    conditions. See the spot-x(7) man page for details.
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  New functions in the library:

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  - spot::iar() and spot::iar_maybe() use index appearance records (IAR)
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    to translate Rabin-like automata into equivalent parity automata.
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    This translation preserves determinism and is especially useful when
    the input automaton is deterministic.

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  - spot::print_aiger() encodes an automaton as an AIGER circuit, as
    required by the SYNTCOMP competition.  It relies on a new named
    property "synthesis outputs" that describes which atomic
    propositions are to be encoded as outputs of the circuits.

  - spot::dnf_to_streett() converts any automaton with a DNF
    acceptance condition into a Streett-like automaton.

  - spot::nsa_to_nca(), spot::dfn_to_nca(), spot::dfn_to_dca(), and
    spot::nsa_to_dca(), convert automata with DNF or Streett-like
    acceptance into deterministic or non-deterministic co-Büchi
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    automata.  spot::to_dca() and spot::to_nca() dispatch between
    these four functions.  The language of produced automaton includes
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    the original language, but may be larger if the original automaton
    is not co-Büchi realizable.  Based on Boker & Kupferman FOSSACS'11
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    paper.  Currently only supports state-based output.
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  - spot::scc_info::states_on_acc_cycle_of() returns all states
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    visited by any accepting cycle of the specified SCC.  It only
    works on automata with Streett-like acceptance.

  - spot::is_recurrence(), spot::is_persistence(), and
    spot::is_obligation() test if a formula is a recurrence,
    persistance or obligation.  The SPOT_PR_CHECK and SPOT_O_CHECK
    environment variables can be used to select between multiple
    implementations of these functions (see the spot-x(7) man page).

  - spot::is_colored() checks if an automaton is colored
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    (i.e., every transition belongs to exactly one acceptance set).
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  - spot::change_parity() converts between different parity acceptance
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    conditions.
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  - spot::colorize_parity() transforms an automaton with parity
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    acceptance into a colored automaton (which is often what people
    working with parity automata expect).
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  - spot::cleanup_parity_acceptance() simplifies a parity acceptance
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    condition.
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  - spot::parity_product() and spot::parity_product_or() are
    specialized (but expensive) products that preserve parity
    acceptance.
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  - spot::remove_univ_otf() removes universal transitions on the fly
    from an alternating Büchi automaton using Miyano and Hayashi's
    breakpoint algorithm.
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  - spot::stutter_invariant_states(),
    spot::stutter_invariant_letters(),
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    spot::highlight_stutter_invariant_states(), ...  These functions
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    help study a stutter-sensitive automaton and detect the subset of
    states that are stutter-invariant.  See
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    https://spot.lrde.epita.fr/ipynb/stutter-inv.html for examples.
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  - spot::acc_cond::name(fmt) is a new method that names well-known
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    acceptance conditions.  The fmt parameter specifies the format to
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    use for that name (e.g. to the style used in HOA, or that used by
    print_dot()).
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  - spot::formula::is_leaf() method can be used to detect formulas
    without children (atomic propositions, or constants).
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  - spot::nesting_depth() computes the nesting depth of any LTL
    operator.
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  - spot::check_determinism() sets both prop_semi_deterministic()
    and prop_universal() appropriately.
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  Improvements to existing functions in the library:

  - spot::tgba_determinize() has been heavily rewritten and
    optimized. The algorithm has (almost) not changed, but it is
    much faster now. It also features an optimization for
    stutter-invariant automata that may produce slightly smaller
    automata.

  - spot::scc_info now takes an optional argument to disable some
    features that are expensive and not always necessary.  By
    default scc_info tracks the list of all states that belong to an
    SCC (you may now ask it not to), tracks the successor SCCs of
    each SCC (that can but turned off), and explores all SCCs of the
    automaton (you may request to stop on the first SCC that is
    found accepting).

  - In some cases, spot::degeneralize() would output Büchi automata
    with more SCCs than its input.  This was hard to notice, because
    very often simulation-based simplifications remove those extra
    SCCs.  This situation is now detected by spot::degeneralized()
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    and fixed before returning the automaton.  A new optional
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    argument can be passed to disable this behavior (or use -x
    degen-remscc=0 from the command-line).

  - The functions for detecting stutter-invariant formulas or
    automata have been overhauled.  Their interface changed
    slightly.  They are now fully documented.

  - spot::postprocessor::set_type() can now request different forms
    of parity acceptance as output.  However currently the
    conversions are not very smart: if the input does not already
    have parity acceptance, it will simply be degeneralized or
    determinized.

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  - spot::postprocessor::set_type() can now request co-Büchi
    acceptance as output.  This calls the aforementioned to_nca() or
    to_dca() functions.

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  - spot::remove_fin() will now call simplify_acceptance(),
    introduced in 2.4, before attempting its different Fin-removal
    strategies.

  - spot::simplify_acceptance() was already merging identical
    acceptance sets, and detecting complementary sets i and j to
    perform the following simplifications
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      Fin(i) & Inf(j) = Fin(i)
      Fin(i) | Inf(j) = Inf(i)
    It now additionally applies the following rules (again assuming i
    and j are complementary):
      Fin(i) & Fin(j) = f          Inf(i) | Inf(j) = t
      Fin(i) & Inf(i) = f          Fin(i) | Inf(i) = t

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  - spot::formula::map(fun) and spot::formula::traverse(fun) will
    accept additionnal arguments and pass them to fun().  See
    https://spot.lrde.epita.fr/tut03.html for some examples.

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  - The "product-states" property of automata is now accessible via
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    spot.twa.get_product_states() and spot.twa.set_product_states().
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  - twa_word instances can be displayed as SVG pictures, with one
    signal per atomic proposition.  For some examples, see the use of
    the show() method in https://spot.lrde.epita.fr/ipynb/word.html

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  - The test suite is now using v4 of the Jupyter Notebook format.

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  - The function rabin_is_buchi_realizable() as its name suggests checks
    if a rabin aut. is Büchi realizable. It is heavily based on
    tra_to_tba() algorithm.

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  Deprecation notices:

  (These functions still work but compilers emit warnings.)

  - spot::scc_info::used_acc(), spot::scc_info::used_acc_of() and
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    spot::scc_info::acc() are deprecated.  They have been renamed
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    spot::scc_info::marks(), spot::scc_info::marks_of() and
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    spot::scc_info::acc_sets_of() respectively for clarity.
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  Backward incompatible changes:

  - The spot::closure(), spot::sl2(), spot::is_stutter_invariant()
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    functions no longer take && arguments.  The former two have
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    spot::closure_inplace() and spot::sl2_inplace() variants.  These
    functions also do not take a list of atomic propositions as an
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    argument anymore.

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    They were not used at all in Spot, and it is not Spot's objective
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    to provide such random functions.

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    been removed.  This low-level function was not used anywhere in
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    Spot anymore, since it's better to use spot::twa::copy_ap_of().

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  Bugs fixed:

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  - spot::simplify_acceptance() could produce incorrect output if the
    first edge of the automaton was the only one with no acceptance
    set.  In spot 2.4.x this function was only used by autfilt
    --simplify-acceptance; in 2.5 it is now used in remove_fin().
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  - spot::streett_to_generalized_buchi() could generate incorrect
    automata with empty language if some Fin set did not intersect all
    accepting SCCs (in other words, the fix from 2.4.1 was incorrect).

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  - ltlcross could crash when calling remove_fin() on an automaton
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    with 32 acceptance sets that would need an additional set.
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  - the down_cast() helper function used in severaly headers of Spot
    was not in the spot namespace, and caused issues with some
    configurations of GCC.

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New in spot 2.4.4 (2017-12-25)
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  Bugs fixed:

  - The generic to_generalized_buchi() function would fail if the
    Fin-less & CNF version of the acceptance condition had several
    unit clauses.

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  - If the automaton passed to sbacc() was incomplete or
    non-deterministic because of some unreachable states, then it was
    possible that the output would marked similarly while it was in
    fact complete or deterministic.
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New in spot 2.4.3 (2017-12-19)
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  Bugs fixed:
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  - couvreur99_new() leaked memory when processing TωA that allocate
    states.

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  - Some mismatched placement-new/delete reported by ASAN were fixed.

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  - Static compilation was broken on MinGW.

  - Execution of Jupyter notebooks from the testsuite failed with
    recent versions of Python.

  - Fix some warnings triggered by the development version of g++.

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New in spot 2.4.2 (2017-11-07)

  Tools:

  - ltlcross and ltldo support ltl3tela, the new name of ltl3hoa.
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  Bugs fixed:

  - Automata produced by "genaut --ks-nca=N" were incorrectly marked
    as not complete.

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  - Fix some cases for which the highest setting of formulas
    simplification would produce worse results than lower settings.

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New in spot 2.4.1 (2017-10-05)
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  Bugs fixed:

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  - The formula class failed to build {a->c[*]} although it is
    allowed by our grammar.
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  - spot::scc_info::determine_unknown_acceptance() incorrectly
    considered some rejecting SCC as accepting.

  - spot::streett_to_generalized_buchi() could generate automata with
    empty language if some Fin set did not intersect all accepting
    SCCs.  As a consequence, some Streett-like automata were
    considered empty even though they were not.  Also, the same
    function could crash on input that had a Streett-like acceptance
    not using all declared sets.

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  - The twa_graph::merge_edges() function relied on BDD IDs to sort
    edges.  This in turn caused some algorithms (like the
    degeneralization) to produce slighltly different (but still correct)
    outputs depending on the BDD operations performed before.
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  - spot::simulation() could incorrectly flag an automaton as
    non-deterministic.
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New in spot 2.4 (2017-09-06)
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  Build:

  - Spot is now built in C++14 mode, so you need at least GCC 5 or
    clang 3.4.  The current version of all major linux distributions
    ship with at least GCC 6, which defaults to C++14, so this should
    not be a problem.  In *this* release of Spot, most of the header
    files are still C++11 compatible, so you should be able to include
    Spot in a C++11 project in case you do not yet want to upgrade.
    There is also an --enable-c++17 option to configure in case you
    want to force a build of Spot in C++17 mode.

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  Tools:

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  - genaut is a new binary that produces families of automata defined
    in the literature (in the same way as we have genltl for LTL
    formulas).

  - autcross is a new binary that compares the output of tools
    transforming automata (in the same way as we have ltlcross for
    LTL translators).

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  - genltl learned two generate two new families of formulas:
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      --fxg-or=RANGE         F(p0 | XG(p1 | XG(p2 | ... XG(pn))))
      --gxf-and=RANGE        G(p0 & XF(p1 & XF(p2 & ... XF(pn))))
    The later is a generalization of --eh-pattern=9, for which a
    single state TGBA always exists (but previous version of Spot
    would build larger automata).

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  - autfilt learned to build the union (--sum) or the intersection
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    (--sum-and) of two languages by putting two automata side-by-side
    and fiddling with the initial states.  This complements the already
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    implemented intersection (--product) and union (--product-or),
    both based on a product.
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  - autfilt learned to complement any alternating automaton with
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    option --dualize.   (See spot::dualize() below.)
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  - autfilt learned --split-edges to convert labels that are Boolean
    formulas into labels that are min-terms.  (See spot::split_edges()
    below.)

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  - autfilt learned --simplify-acceptance to simplify some acceptance
    conditions.  (See spot::simplify_acceptance() below.)

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  - autfilt --decompote-strength has been renamed to --decompose-scc
    because it can now extract the subautomaton leading to an SCC
    specified by number.  (The old name is still kept as an alias.)

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  - The --stats=%c option of tools producing automata can now be
    restricted to count complete SCCs, using %[c]c.

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  - Tools producing automata have a --stats=... option, and tools
    producing formulas have a --format=... option.  These two options
    work similarly, the use of different names is just historical.
    Starting with this release, all tools that recognize one of these
    two options also accept the other one as an alias.

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  Library:

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  - A new library, libspotgen, gathers all functions used to generate
    families of automata or LTL formulas, used by genltl and genaut.
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  - spot::sum() and spot::sum_and() implements the union and the
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    intersection of two automata by putting them side-by-side and
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    using non-deterministim or universal branching on the initial
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    state.
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  - twa objects have a new property: prop_complete().  This obviously
    acts as a cache for the is_complete() function.

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  - spot::dualize() complements any alternating automaton.  Since
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    the dual of a deterministic automaton is still deterministic, the
    function spot::dtwa_complement() has been deprecated and simply
    calls spot::dualize().
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  - spot::decompose_strength() was extended and renamed to
    spot::decompose_scc() as it can now also extract a subautomaton
    leading to a particular SCC.  A demonstration of this feature via
    the Python bindings can be found at
    https://spot.lrde.epita.fr/ipynb/decompose.html

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  - The print_dot() function will now display names for well known
    acceptance conditions under the formula when option 'a' is used.
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    We plan to enable 'a' by default in a future release, so a new
    option 'A' has been added to hide the acceptance condition.
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  - The print_dot() function has a new experimental option 'x' to
    output labels are LaTeX formulas.  This is meant to be used in
    conjunction with the dot2tex tool.  See
      https://spot.lrde.epita.fr/oaut.html#dot2tex

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  - A new named property for automata called "original-states" can be
    used to record the origin of a state before transformation.  It is
    currently defined by the degeneralization algorithms, and by
    transform_accessible() and algorithms based on it (like
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    remove_ap::strip(), decompose_scc()).  This is realy meant as an
    aid for writing algorithms that need this mapping, but it can also
    be used to debug these algorithms: the "original-states"
    information is displayed by the dot printer when the 'd' option is
    passed.  For instance in
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      % ltl2tgba 'GF(a <-> Fb)' --dot=s
      % ltl2tgba 'GF(a <-> Fb)' | autfilt -B --dot=ds

    the second command outputs an automaton with states that show
    references to the first one.

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  - A new named property for automata called "degen-levels" keeps track
    of the level of a state in a degeneralization. This information
    complements the one carried in "original-states".

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  - A new named property for automata called "simulated-states" can be
    used to record the origin of a state through simulation. The
    behavior is similar to "original-states" above. Determinization
    takes advantage of this in its pretty print.

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  - The new function spot::acc_cond::is_streett_like() checks whether
    an acceptance condition is conjunction of disjunctive clauses
    containing at most one Inf and at most one Fin.  It builds a
    vector of pairs to use if we want to assume the automaton has
    Streett acceptance.  The dual function is
    spot::acc_cond::is_rabin_like() works similarly.
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  - The degeneralize() function has learned to consider acceptance
    marks common to all edges comming to a state to select its initial
    level.  A similar trick was already used in sbacc(), and saves a
    few states in some cases.

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  - There is a new spot::split_edges() function that transforms edges
    (labeled by Boolean formulas over atomic propositions) into
    transitions (labeled by conjunctions where each atomic proposition
    appear either positive or negative).  This can be used to
    preprocess automata before feeding them to algorithms or tools
    that expect transitions labeled by letters.

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  - spot::scc_info has two new methods to easily iterate over the
    edges of an SCC: edges_of() and inner_edges_of().

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  - spot::scc_info can now be passed a filter function to ignore
    or cut some edges.

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  - spot::scc_info now keeps track of acceptance sets that are common
    to all edges in an SCC.  These can be retrieved using
    scc_info::common_sets_of(scc), and they are used by scc_info to
    classify some SCCs as rejecting more easily.

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  - The new function acc_code::remove() removes all the given
    acceptance sets from the acceptance condition.

  - It is now possible to change an automaton acceptance condition
    directly by calling twa::set_acceptance().

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  - spot::cleanup_acceptance_here now takes an additional boolean
    parameter specifying whether to strip useless marks from the
    automaton.  This parameter is defaulted to true, in order to
    keep this modification backward-compatible.

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  - The new function spot::simplify_acceptance() is able to perform
    some simplifications on an acceptance condition, and might lead
    to the removal of some acceptance sets.

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  - The function spot::streett_to_generalized_buchi() is now able to
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    work on automata with Streett-like acceptance.
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  - The function for converting deterministic Rabin automata to
    deterministic Büchi automata (when possible), internal to the
    remove_fin() procedure, has been updated to work with
    transition-based acceptance and with Rabin-like acceptance.

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  - spot::relabel_here() was used on automata to rename atomic
    propositions, it can now replace atomic propositions by Boolean
    subformula.  This makes it possible to use relabeling maps
    produced by relabel_bse() on formulas.
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  - twa_graph::copy_state_names_from() can be used to copy the state
    names from another automaton, honoring "original-states" if
    present.

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  - Building automata for LTL formula with a large number N of atomic
    propositions can be costly, because several loops and
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    data-structures are exponential in N.  However a formula like
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      ((a & b & c) | (d & e & f)) U ((d & e & f) | (g & h & i))
    can be translated more efficiently by first building an automaton
    for (p0 | p1) U (p1 | p2), and then substituting p0, p1, p2 by the
    appropriate Boolean formula.  Such a trick is now attempted
    for translation of formulas with 4 atomic propositions or
    more (this threshold can be changed, see -x relabel-bool=N in
    the spot-x(7) man page).

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  - The LTL simplification routines learned that an LTL formula like
    G(a & XF(b & XFc & Fd) can be simplified to G(a & Fb & Fc & Fd),
    and dually F(a | XG(b | XGc | Gd)) = F(a | Gb | Gc | Gd).

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    When working with SERE, the simplification of "expr[*0..1]" was
    improved.  E.g. {{a[*]|b}[*0..1]} becomes {a[*]|b} instead of
    {{a[+]|b}[*0..1]}.

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  - The new function spot::to_weak_alternating() is able to take an
    input automaton with generalized Büchi/co-Büchi acceptance and
    convert it to a weak alternating automaton.

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  - spot::sbacc() is can now also convert alternating automata
    to state-based acceptance.
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  - spot::sbacc() and spot::degeneralize() learned to merge
    accepting sinks.

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  - If the SPOT_BDD_TRACE environment variable is set, statistics
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    about BDD garbage collection and table resizing are shown.

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  - The & and | operators for acceptannce conditions have been changed
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    slightly to be more symmetrical.  In older versions, operator &
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    would move Fin() terms to the front, but that is not the case
    anymore.  Also operator & was already grouping all Inf() terms
    (for efficiency reasons), in this version operator | is
    symmetrically grouping all Fin() terms.
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  - The automaton parser is now reentrant, making it possible to
    process automata from different streams at the same time (i.e.,
    using multiple spot::automaton_stream_parser instances at once).

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  - The print_hoa() and parse_automaton() functions have been updated
    to recognize the "exist-branch" property of the non-released HOA
    v1.1, as well as the new meaning of property "deterministic".  (In
    HOA v1 "properties: deterministic" means that the automaton has no
    existential branching; in HOA v1.1 it disallows universal
    branching as well.)  The meaning of "deterministic" in Spot has
    been adjusted to these new semantics, see "Backward-incompatible
    changes" below.

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  - The parser for HOA now recognizes and verifies correct use of the
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    "univ-branch" property.  This is known to be a problem with option
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    -H1 of ltl3ba 1.1.2 and ltl3dra 0.2.4, so the environment variable
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    SPOT_HOA_TOLERANT can be set to disable the diagnostic.

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  Python:

  - The 'spot.gen' package exports the functions from libspotgen.
    See https://spot.lrde.epita.fr/ipynb/gen.html for examples.

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  Bugs fixed:

  - When the remove_fin() function was called on some automaton with
    Inf-less acceptance involving at least one disjunction (e.g.,
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    generalized co-Büchi), it would sometimes output an automaton with
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    transition-based acceptance but marked as state-based.

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  - The complete() function could complete an empty co-Büchi automaton
    into an automaton accepting everything.
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  Backward-incompatible changes:

  - spot::acc_cond::mark_t::operator bool() has been marked as
    explicit.  The implicit converion to bool (and, via bool, to int)
    was a source of bugs.

  - spot::twa_graph::set_init_state(const state*) has been removed.
    It was never used.  You always want to use
    spot::twa_graph::set_init_state(unsigned) in practice.

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  - The previous implementation of spot::is_deterministic() has been
    renamed to spot::is_universal().  The new version of
    spot::is_deterministic() requires the automaton to be both
    universal and existential.  This should not make any difference in
    existing code unless you work with the recently added support for
    alternating automata.

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  - spot::acc_cond::mark_t::sets() now returns an internal iterable
    object instead of an std::vector<unsigned>.

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  - The color palette optionally used by print_dot() has been extended
    from 9 to 16 colors.  While the first 8 colors are similar, they
    are a bit more saturated now.

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  deprecation notices:
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  (these functions still work but compilers emit warnings.)
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  - spot::decompose_strength() is deprecated, it has been renamed
    to spot::decompose_scc().

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  - spot::dtwa_complement() is deprecated.  prefer the more generic
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    spot::dualize() instead.

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  - the spot::twa::prop_deterministic() methods have been renamed to
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    spot::twa::prop_universal() for consistency with the change to
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    is_deterministic() listed above.  we have kept
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    spot::twa::prop_deterministic() as a deprecated synonym for
    spot::twa::prop_universal() to help backward compatibility.
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  - the spot::copy() function is deprecated.  use
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    spot::make_twa_graph() instead.

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New in spot 2.3.5 (2017-06-22)
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  Bugs fixed:

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  - We have fixed new cases where translating multiple formulas in a
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    single ltl2tgba run could produce automata different from those
    produced by individual runs.
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  - The print_dot() function had a couple of issues when printing
    alternating automata: in particular, when using flag 's' (display
    SCC) or 'y' (split universal destination by colors) universal
    edges could be connected to undefined states.

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  - Using --stats=%s or --stats=%s or --stats=%t could take an
    unnecessary long time on automata with many atomic propositions,
    due to a typo.  Furthermore, %s/%e/%t/%E/%T were printing
    a number of reachable states/edges/transitions, but %S was
    incorrectly counting all states even unreachable.

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  - Our verson of BuDDy had an incorrect optimization for the
    biimp operator.

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New in spot 2.3.4 (2017-05-11)
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  Bugs fixed:

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  - The transformation to state-based acceptance (spot::sbacc()) was
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    incorrect on automata where the empty acceptance mark is accepting.
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  - The --help output of randaut and ltl2tgba was showing an
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    unsupported %b stat.

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  - ltldo and ltlcross could leave temporary files behind when
    aborting on error.

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  - The LTL simplifcation rule that turns F(f)|q into F(f|q)
    when q is a subformula that is both eventual and universal
    was documented but not applied in some forgotten cases.

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  - Because of some caching inside of ltl2tgba, translating multiple
    formula in single ltl2tgba run could produce automata different
    from those produced by individual runs.

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New in spot 2.3.3 (2017-04-11)
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  Tools:

  - ltldo and ltlcross learned shorthands to talk to ltl2da, ltl2dpa,
    and ltl2ldba (from Owl) without needing to specify %f>%O.

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  - genltl learned --spec-patterns as an alias for --dac-patterns; it
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    also learned two new sets of LTL formulas under --hkrss-patterns
    (a.k.a. --liberouter-patterns) and --p-patterns
    (a.k.a. --beem-patterns).
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  Bugs fixed:
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  - In "lenient" mode the formula parser would fail to recover from a
    missing closing brace.
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  - The output of 'genltl --r-left=1 --r-right=1 --format=%F' had
    typos.
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  - 'ltl2tgba Fa | autfilt --complement' would incorrectly claim that
    the output is "terminal" because dtwa_complement() failed to reset
    that property.

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  - spot::twa_graph::purge_unreachable_states() was misbehaving on
    alternating automata.

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  - In bench/stutter/ the .cc files were not compiling due to warnings
    being caught as errors.
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  - The code in charge of detecting DBA-type Rabin automata is
    actually written to handle a slightly larger class of acceptance
    conditions (e.g., Fin(0)|(Fin(1)&Inf(2))), however it failed to
    correctly detect DBA-typeness in some of these non-Rabin
    acceptance.

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New in spot 2.3.2 (2017-03-15)
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  Tools:

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  - In tools that output automata, the number of atomic propositions
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    can be output using --stats=%x (output automaton) or --stats=%X
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    (input automaton).  Additional options can be passed to list
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    atomic propositions instead of counting them.  Tools that output
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    formulas also support --format=%x for this purpose.
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  Python:

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  - The bdd_to_formula(), and to_generalized_buchi() functions can now
    be called in Python.
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  Documentation:

  - https://spot.lrde.epita.fr/tut11.html is a new page describing
    how to build monitors in Shell, Python, or C++.

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  Bugs fixed:

  - The tests using LTSmin's patched version of divine would fail
    if the current (non-patched) version of divine was installed.

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  - Because of a typo, the output of --stats='...%P...' was correct
    only if %p was used as well.

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  - genltl was never meant to have (randomly attributed) short
    options for --postive and --negative.