Table of Contents


dstar2tgba - convert automata into Büchi automata


dstar2tgba [OPTION...] [FILENAME[/COL]...]


Convert automata with any acceptance condition into variants of Büchi automata.

This reads automata into any supported format (HOA, LBTT, ltl2dstar, never claim) and outputs a Transition-based Generalized Büchi Automata in GraphViz’s format by default. Each supplied file may contain multiple automata.


-F, --file=FILENAME

process the automaton in FILENAME


If false, properties listed in HOA files are ignored, unless they can be easily verified. If true (the default) any supported property is trusted.

Output automaton type:

-b, --buchi, --Buchi

automaton with Büchi acceptance

-B, --sba, --ba

state-based Büchi Automaton (same as -S -b)

--cobuchi, --coBuchi

automaton with co-Büchi acceptance (will recognize a superset of the input language if not co-Büchi realizable)

-C, --complete

output a complete automaton

-G, --generic

any acceptance condition is allowed

-M, --monitor

Monitor (accepts all finite prefixes of the given property)

-p, --colored-parity[=any|min|max|odd|even|min odd|min even|max odd|max


colored automaton with parity acceptance

-P, --parity[=any|min|max|odd|even|min odd|min even|max odd|max even]

automaton with parity acceptance

-S, --state-based-acceptance, --sbacc

define the acceptance using states

--tgba, --gba

automaton with Generalized Büchi acceptance (default)

Output format:

-8, --utf8

enable UTF-8 characters in output (ignored with --lbtt or --spin)


test for the additional property PROP and output the result in the HOA format (implies -H). PROP may be some prefix of ’all’ (default), ’unambiguous’, ’stutter-invariant’, ’stutter-sensitive-example’, ’semi-determinism’, or ’strength’.

-d, --dot[=1|a|A|b|B|c|C(COLOR)|e|E|f(FONT)|h|i(ID)|k|K|n|N|o|r|R|s|t|

GraphViz’s format. Add letters for (1) force numbered states, (a) show acceptance condition (default), (A) hide acceptance condition, (b) acceptance sets as bullets, (B) bullets except for Büchi/co-Büchi automata, (c) force circular nodes, (C) color nodes with COLOR, (d) show origins when known, (e) force elliptic nodes, (E) force rEctangular nodes, (f(FONT)) use FONT, (g) hide edge labels, (h) horizontal layout, (i) or (i(GRAPHID)) add IDs, (k) use state labels when possible, (K) use transition labels (default), (n) show name, (N) hide name, (o) ordered transitions, (r) rainbow colors for acceptance sets, (R) color acceptance sets by Inf/Fin, (s) with SCCs, (t) force transition-based acceptance, (u) hide true states, (v) vertical layout, (y) split universal edges by color, (+INT) add INT to all set numbers, (<INT) display at most INT states, (#) show internal edge numbers

-H, --hoaf[=1.1|i|k|l|m|s|t|v]

Output the automaton in HOA format (default). Add letters to select (1.1) version 1.1 of the format, (i) use implicit labels for complete deterministic automata, (s) prefer state-based acceptance when possible [default], (t) force transition-based acceptance, (m) mix state and transition-based acceptance, (k) use state labels when possible, (l) single-line output, (v) verbose properties


LBTT’s format (add =t to force transition-based acceptance even on Büchi automata)


set the name of the output automaton

-o, --output=FORMAT

send output to a file named FORMAT instead of standard output. The first automaton sent to a file truncates it unless FORMAT starts with ’>>’.

-q, --quiet

suppress all normal output

-s, --spin[=6|c]

Spin neverclaim (implies --ba). Add letters to select (6) Spin’s 6.2.4 style, (c) comments on states

--stats=FORMAT, --format=FORMAT

output statistics about the automaton

Any FORMAT string may use the following interpreted sequences (capitals for input, minuscules for output):


a single %


the part of the line before the automaton if it comes from a column extracted from a CSV file


the part of the line after the automaton if it comes from a column extracted from a CSV file

%A, %a

number of acceptance sets

%C, %c, %[LETTERS]C, %[LETTERS]c

number of SCCs; you may filter the SCCs to count using the following LETTERS, possibly concatenated: (a) accepting, (r) rejecting, (c) complete, (v) trivial, (t) terminal, (w) weak, (iw) inherently weak. Use uppercase letters to negate them.

%D, %d

1 if the automaton is deterministic, 0 otherwise

%E, %e, %[LETTER]E, %[LETTER]e

number of edges (add one LETTER to select

(r) reachable [default], (u) unreachable, (a)



name of the input file

%G, %g, %[LETTERS]G, %[LETTERS]g

acceptance condition (in HOA syntax); add brackets to print an acceptance name instead and LETTERS to tweak the format: (0) no parameters, (a) accentuated, (b) abbreviated, (d) style used in dot output, (g) no generalized parameter, (l) recognize Street-like and Rabin-like, (m) no main parameter, (p) no parity parameter, (o) name unknown acceptance as ’other’, (s) shorthand for ’lo0’.

%H, %h

the automaton in HOA format on a single line (use %[opt]H or %[opt]h to specify additional options as in --hoa=opt)


location in the input file

%M, %m

name of the automaton

%N, %n

number of nondeterministic states

%P, %p

1 if the automaton is complete, 0 otherwise


wall-clock time elapsed in seconds (excluding



CPU time (excluding parsing), in seconds; Add LETTERS to restrict to (u) user time, (s) system time, (p) parent process, or (c) children processes.

%S, %s, %[LETTER]S, %[LETTER]s

number of states (add one LETTER to select

(r) reachable [default], (u) unreachable, (a)


%T, %t, %[LETTER]E, %[LETTER]e

number of transitions (add one LETTER to

select (r) reachable [default], (u) unreachable,

(a) all).

%U, %u, %[LETTER]U, %[LETTER]u

1 if the automaton contains some universal

branching (or a number of [s]tates or [e]dges with

universal branching)

%W, %w

one word accepted by the automaton

%X, %x, %[LETTERS]X, %[LETTERS]x

number of atomic propositions declared in the

add LETTERS to list atomic

propositions with (n) no quoting, (s) occasional

double-quotes with C-style escape, (d) double-quotes with C-style escape, (c) double-quotes with CSV-style escape, (p) between parentheses, any extra non-alphanumeric character will be used to separate propositions

Simplification goal:

-a, --any

no preference, do not bother making it small or deterministic

-D, --deterministic

prefer deterministic automata (combine with --generic to be sure to obtain a deterministic automaton)


prefer small automata (default)

Simplification level:


all available optimizations (slow, default)


minimal optimizations (fast)


moderate optimizations

Miscellaneous options:

-x, --extra-options=OPTS

fine-tuning options (see spot-x (7))


print this help


print program version

Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options.


dstar2tgba was introduced in Spot 1.2 as a command that reads automata in ltl2dstar’s format, and converts them into TGBA. At this time it was the only command-line tool being able to read automata.

In Spot 1.99.1 the autfilt command was introduced, but could only read automata in the HOA format, or in lbtt’s format, or as never claims. So dstar2tgba was still the only way to process automata in ltl2dstar’s format.

In Spot 1.99.4 the parser for ltl2dstar’s format was finally merged with the parser used by autfilt for reading the other format. This implies not only that autfilt can now read ltl2dstar’s format, but also that dstar2tgba can read the other formats as well.

Nowadays, the command

% dstar2tgba some files

can be used as a shorthand for

% autfilt --tgba --high --small some files

The name dstar2tgba is kept for backward compatibility and because it is used in at least one published paper, but naming this tool aut2tgba would make more sense.



The ltl2dstarmanual.

Documents the output format of ltl2dstar.


Chistof Löding: Mehods for the Transformation of ω-Automata: Complexity and Connection to Second Order Logic. Diploma Thesis. University of Kiel. 1998.

Describes various tranformations from non-deterministic Rabin and Streett automata to Büchi automata. Slightly optimized variants of these transformations are used by dstar2tgba for the general cases.


Sriram C. Krishnan, Anuj Puri, and Robert K. Brayton: Deterministic ω-automata vis-a-vis Deterministic Büchi Automata. ISAAC’94.

Explains how to preserve the determinism of Rabin and Streett automata when the property can be repreted by a Deterministic automaton. dstar2tgba implements this for the Rabin case only. In other words, translating a deterministic Rabin automaton with dstar2tgba will produce a deterministic TGBA or BA if such a automaton exists.


Souheib Baarir and Alexandre Duret-Lutz: Mechanizing the minimization of deterministic generalized Büchi automata. Proceedings of FORTE’14. LNCS 8461.

Explains the SAT-based minimization techniques that can be used (on request only) by dstar2tgba to minimize deterministic Büchi automata.


Souheib Baarir and Alexandre Duret-Lutz: SAT-based minimization of deterministic ω-automata. Proceedings of LPAR’15 (a.k.a LPAR-20). LNCS 9450.

Extends the previous paper by allowing arbitrary acceptance conditions.


Report bugs to <spot@lrde.epita.fr>.


Copyright © 2023 Laboratoire de Recherche de l’Epita (LRE) License GPLv3+: GNU GPL version 3 or later.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.


spot-x(7), autfilt(1)