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commit 1d15f74b0ec8492ed44f154e3d376bd6fbeda9d3
parent f42898f84f04c1b41e0e37e2f2f5c5649a7b58b4
Author: Antoine Amarilli <a3nm@a3nm.net>
Date:   Thu, 18 Sep 2025 20:00:38 +0200

commit with codex

Diffstat:
2_ambiguous_cfg | 3+++
context_free_grammar | 3+++
context_free_grammar_ambiguity_problem | 9+++++++++
context_free_grammar_equivalence | 2++
context_free_grammar_inclusion | 7+++++++
context_free_grammar_unambiguous | 1+
language_inclusion | 1+
7 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/2_ambiguous_cfg b/2_ambiguous_cfg @@ -2,6 +2,9 @@ A *2-ambiguous CFG* is an [ambiguous_CFG] where every [word] has at most two [parse_trees] +- [universality_2_ambiguous_CFG] +- [equivalence_2_ambiguous_CFG] + Up: [degree_of_ambiguity_cfg] Aliases: 2 ambiguous CFGs, 2ambiguous CFG, 2ambiguous CFGs diff --git a/context_free_grammar b/context_free_grammar @@ -35,9 +35,11 @@ ## Problems - [context_free_grammar_equivalence] +- [context_free_grammar_inclusion] - [context_free_grammar_universality] - [smallest_grammar_problem] - [context_free_grammar_membership] +- [context_free_grammar_ambiguity_problem] ## Fields @@ -46,6 +48,7 @@ ## Extensions - [probabilistic_grammar] +- [conjunctive_grammar] - [multiple_context_free_grammar] ## Results diff --git a/context_free_grammar_ambiguity_problem b/context_free_grammar_ambiguity_problem @@ -0,0 +1,9 @@ +# Context free grammar ambiguity problem + +The [computational_problem] of [deciding] if a [CFG] is [uCFG] + +Already [undecidable] for very restricted [linear_CFGs] by reduction from [PCP] + +Up: [ambiguity_problem], [context_free_grammar] + +See also: [context_free_language_inherent_ambiguity_problem] diff --git a/context_free_grammar_equivalence b/context_free_grammar_equivalence @@ -7,3 +7,5 @@ Two [CFGs] are *equivalent* if they recognize the same [formal_language] Up: [context_free_grammar], [language_equivalence] Aliases: CFG equivalence, CFG equivalent, equivalent CFG, grammar equivalent + +See also: [context_free_grammar_inclusion] diff --git a/context_free_grammar_inclusion b/context_free_grammar_inclusion @@ -0,0 +1,7 @@ +# Context free grammar inclusion + +It is [undecidable], already for [uCFLs], and already for [linear_uCFLs], see [asveld2000note] + +Up: [inclusion_problem], [context_free_grammar] + +Aliases: CFG inclusion diff --git a/context_free_grammar_unambiguous b/context_free_grammar_unambiguous @@ -10,6 +10,7 @@ There are some [CFLs] admitting no uCFG (namely, those that are not [uCFLs]), an [Computational_problems]: - [unambiguous_cfg_equivalence_problem] +- [unambiguous_cfg_inclusion_problem] - [unambiguous_cfg_universality] Up: [unambiguity], [context_free_grammar] diff --git a/language_inclusion b/language_inclusion @@ -4,5 +4,6 @@ - [language_inclusion_bounded] - [DPDA_language_inclusion] - [automaton_inclusion] +- [CFG_language_inclusion] Up: [formal_language_computational_problems], [set_inclusion]