LTLFILT(1)

NAME
ltlfilt - filter files or lists of LTL/PSL formulas

SYNOPSIS
ltlfilt [OPTION...] [FILENAME[/COL]...]

DESCRIPTION

Read a list of formulas and output them back after some optional processing.

  Input options:

-f, --formula=STRING
    process the formula STRING

-F, --file=FILENAME[/COL]
    process each line of FILENAME as a formula; if COL is a positive integer, assume a CSV file and read column COL; use a negative COL to drop the first line of the CSV file

--lbt-input
    read all formulas using LBT's prefix syntax

--lenient
    parenthesized blocks that cannot be parsed as subformulas are considered as atomic properties

  Error handling:

--drop-errors
    discard erroneous lines (default)

--ignore-errors
    do not report syntax errors

--skip-errors
    output erroneous lines as-is without processing

  Transformation options:

--boolean-to-isop
    rewrite Boolean subformulas as irredundant sum of products (implies at least -r1)

--define[=FILENAME]
    when used with --relabel or --relabel-bool, output the relabeling map using #define statements

--exclusive-ap=AP,AP,...
    if any of those APs occur in the formula, add a term ensuring two of them may not be true at the same time. Use this option multiple times to declare independent groups of exclusive propositions.

--from-ltlf[=alive]
    transform LTLf (finite LTL) to LTL by introducing some 'alive' proposition

--ins=PROPS, --inputs=PROPS
    comma-separated list of input atomic propositions to use with --relabel=io or --save-part-file, interpreted as a regex if enclosed in slashes

--negate
    negate each formula

--nnf
    rewrite formulas in negative normal form

--outs=PROPS, --outputs=PROPS
    comma-separated list of output atomic propositions to use with --relabel=io or --save-part-file, interpreted as a regex if enclosed in slashes

--part-file=FILENAME
    file containing the partition of atomic propositions to use with --relabel=io

--relabel[=abc|pnn|io] relabel all atomic propositions, alphabetically
    unless specified otherwise

--relabel-bool[=abc|pnn]
    relabel Boolean subexpressions that do not share atomic propositions, relabel alphabetically unless specified otherwise

--relabel-overlapping-bool[=abc|pnn]
    relabel Boolean subexpressions even if they share atomic propositions, relabel alphabetically unless specified otherwise

--remove-wm
    rewrite operators W and M using U and R (this is an alias for --unabbreviate=WM)

--remove-x
    remove X operators (valid only for stutter-insensitive properties)

-r, --simplify[=LEVEL]
    simplify formulas according to LEVEL (see below); LEVEL is set to 3 if omitted

--save-part-file[=FILENAME]
    file containing the partition of atomic propositions, readable by --part-file

--sonf[=PREFIX]
    rewrite formulas in suffix operator normal form

--sonf-aps[=FILENAME]
    when used with --sonf, output the newly introduced atomic propositions

--to-delta2
    rewrite LTL formula in Δ₂-form

--unabbreviate[=STR]
    remove all occurrences of the operators specified by STR, which must be a substring of "eFGiMRW^", where 'e', 'i', and '^' stand respectively for <->, ->, and xor. If no argument is passed, the subset "eFGiMW^" is used.

--unobservable-ins=PROPS, --unobservable-inputs=PROPS
    comma-separated list of unobservable and uncontrollable atomic propositions, to use with --relabel=io or --save-part-file, interpreted as a regex if enclosed in slashes

The simplification LEVEL may be set as follows.

0   No rewriting

1   basic rewritings and eventual/universal rules

2   additional syntactic implication rules

3   better implications using containment

  Filtering options (matching is done after transformation):

--accept-word=WORD
    keep formulas that accept WORD

--ap=RANGE
    match formulas with a number of atomic propositions in RANGE

--boolean
    match Boolean formulas

--bsize=RANGE
    match formulas with Boolean size in RANGE

--delta1
    match Δ₁ formulas

--delta2
    match Δ₂ formulas

--equivalent-to=FORMULA
    match formulas equivalent to FORMULA

--eventual
    match pure eventualities

--guarantee
    match guarantee formulas (even pathological)

--implied-by=FORMULA
    match formulas implied by FORMULA

--imply=FORMULA
    match formulas implying FORMULA

--liveness
    match liveness properties

--ltl
    match only LTL formulas (no PSL operator)

-N, --nth=RANGE
    assuming input formulas are numbered from 1, keep only those in RANGE

--obligation
    match obligation formulas (even pathological)

--persistence
    match persistence formulas (even pathological)

--pi2
    match Π₂ formulas

--recurrence
    match recurrence formulas (even pathological)

--reject-word=WORD
    keep formulas that reject WORD

--safety
    match safety formulas (even pathological)

--satisfiable
    match satisfiable formulas

--sigma2
    match Σ₂ formulas

--size=RANGE
    match formulas with size in RANGE

--stutter-insensitive, --stutter-invariant
    match stutter-insensitive LTL formulas

--suspendable
    synonym for --universal --eventual

--syntactic-guarantee, --sigma1
    match syntactic-guarantee (a.k.a. Σ₁) formulas

--syntactic-obligation
    match syntactic-obligation formulas

--syntactic-persistence
    match syntactic-persistence formulas

--syntactic-recurrence
    match syntactic-recurrence formulas

--syntactic-safety, --pi1
    match syntactic-safety (a.k.a. Π₁) formulas

--syntactic-stutter-invariant, --nox
    match stutter-invariant formulas syntactically (LTL-X or siPSL)

--universal
    match purely universal formulas

-u, --unique
    drop formulas that have already been output (not affected by -v)

-v, --invert-match
    select non-matching formulas

RANGE may have one of the following forms: 'INT', 'INT..INT', '..INT', or 'INT..'

WORD is lasso-shaped and written as 'BF;BF;...;BF;cycle{BF;...;BF}' where BF are arbitrary Boolean formulas. The 'cycle{...}' part is mandatory, but the prefix can be omitted.

  Output options:

-0, --zero-terminated-output
    separate output formulas with \0 instead of \n (for use with xargs -0)

-8, --utf8
    output using UTF-8 characters

-c, --count
    print only a count of matched formulas

--format=FORMAT, --stats=FORMAT
    specify how each line should be output (default: "%f")

-l, --lbt
    output in LBT's syntax

--latex
    output using LaTeX macros

-n, --max-count=NUM
    output at most NUM formulas

-o, --output=FORMAT
    send output to a file named FORMAT instead of standard output. The first formula sent to a file truncates it unless FORMAT starts with '>>'.

-p, --full-parentheses
    output fully-parenthesized formulas

-q, --quiet
    suppress all normal output

-s, --spin
    output in Spin's syntax

--spot
    output in Spot's syntax (default)

--wring
    output in Wring's syntax

The FORMAT string passed to --format may use the following interpreted sequences:

%<  the part of the line before the formula if it comes from a column extracted from a CSV file

%>  the part of the line after the formula if it comes from a column extracted from a CSV file

%%  a single %

%b  the Boolean-length of the formula (i.e., all Boolean subformulas count as 1)

%f  the formula (in the selected syntax)

%F  the name of the input file

%h, %[vw]h
    the class of the formula is the Manna-Pnueli hierarchy ([v] replaces abbreviations by class names, [w] for all compatible classes)

%l  the serial number of the output formula

%L  the original line number in the input file

%[OP]n
    the nesting depth of operator OP. OP should be a single letter denoting the operator to count, or multiple letters to fuse several operators during depth evaluation. Add '~' to rewrite the formula in negative normal form before counting.

%r  wall-clock time elapsed in seconds (excluding parsing)

%R, %[LETTERS]R
    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  the length (or size) of the formula

%x, %[LETTERS]X, %[LETTERS]x
    number of atomic propositions used in the

formula;
    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

  Miscellaneous options:

--help
    print this help

--version
    print program version

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

  Exit status:

0   if some formulas were output (skipped syntax errors do not count)

1   if no formulas were output (no match)

2   if any error has been reported

BIBLIOGRAPHY
If you would like to give a reference to this tool in an article, we suggest you cite the following paper:

•   Alexandre Duret-Lutz: Manipulating LTL formulas using Spot 1.0. Proceedings of ATVA'13. LNCS 8172.

The following papers describe algorithms used by ltlfilt:

•   Kousha Etessami: A note on a question of Peled and Wilke regarding stutter-invariant LTL. Information Processing Letters 75(6): 261-263 (2000). Describes the transformation behind the --remove-x option.

•   Thibaud Michaud and Alexandre Duret-Lutz: Practical stutter-invariance checks for ω-regular languages. Proceedings of SPIN'15. LNCS 9232. Describes the algorithm used by --stutter-insensitive option.

•   Christian Dax, Jochen Eisinger, Felix Klaedtke: Mechanizing the Powerset Construction for Restricted Classes of ω-Automata. Proceedings of ATVA'07. LNCS 4762. Describes the checks implemented by the --safety, --guarantee, and --obligation options.

•   Ivana Černá, Radek Pelánek: Relating Hierarchy of Temporal Properties to Model Checking. Proceedings of MFCS'03. LNCS 2747. Describes the syntactic LTL classes matched by the --syntactic-safety, --syntactic-guarantee, --syntactic-obligation options, --syntactic-persistence, and --syntactic-recurrence options.

•   Kousha Etessami, Gerard J. Holzmann: Optimizing Büchi Automata. Proceedings of CONCUR'00. LNCS 1877. Describe the syntactic LTL classes matched by --eventual, and --universal.

•   Giuseppe De Giacomo, Moshe Y. Vardi: Linear Temporal Logic and Linear Dynamic Logic on Finite Traces. Proceedings of IJCAI'13. Describe the transformation implemented by --from-ltlf to reduce LTLf model checking to LTL model checking.

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

COPYRIGHT
Copyright © 2025 by the Spot authors, see the AUTHORS File for details. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
randltl(1), ltldo(1)