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Project-declaredLean 4.33.0-rc1 · mathlib@169c26b52a38

Inter language eq

Cslib.Automata.NA.Buchi.inter_language_eq

Plain-language statement

The language accepted by the intersection automaton is the intersection of the languages accepted by the two component automata.

Exact Lean statement

@[simp, scoped grind =]
theorem inter_language_eq :
    language (Buchi.mk (interNA na acc) (interAccept acc)) =
    ⨅ i, language (Buchi.mk (na i) (acc i))

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
@[simp, scoped grind =]theorem inter_language_eq :    language (Buchi.mk (interNA na acc) (interAccept acc)) =    ⨅ i, language (Buchi.mk (na i) (acc i)) := by  apply mem_ext  intro xs  simp only [ωLanguage.mem_iInf]  constructor  · intro ss, h_run, h_inf i    use ss.map (fun s  s.fst i)    constructor    · apply iProd_run_iff.mp <| hist_run_proj h_run    · simp only [interAccept, mem_union, frequently_or_distrib] at h_inf      cases i      · rcases h_inf with h_inf_f | h_inf_t        · apply Frequently.mono h_inf_f          grind        · apply Frequently.mono <| inter_freq_acc_freq_acc h_run h_inf_t          grind      · rcases h_inf with h_inf_f | h_inf_t        · apply Frequently.mono <| inter_freq_acc_freq_acc h_run h_inf_f          grind        · apply Frequently.mono h_inf_t          grind  · intro h    choose ss_i h_ss_i using h    let ss_p : ωSequence (Π i, State i) := fun k i  ss_i i k    have h_ss_p : (iProd na).Run xs ss_p := by      grind only [Run, = iProd_run_iff, = get_fun, = LTS.OmegaExecution, = get_map]    have (k : ) (i : Bool) : ss_p k i = ss_i i k := rfl    obtain ss, h_run, _ := hist_run_exists h_ss_p    use ss, h_run    apply inter_freq_comp_acc_freq_acc h_run    · apply Frequently.mono (h_ss_i false).2      grind    · apply Frequently.mono (h_ss_i true).2      grind
Project
Lean Computer Science Library
License
Apache-2.0
Commit
f36649cff2c9
Source
Cslib/Computability/Automata/NA/BuchiInter.lean:99-135

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Related declarations

Project-declaredLean 4.33.0-rc1

Unique minimal

Cslib.Automata.DA.FinAcc.unique_minimal

Plain-language statement

The minimal DFA M accepting the language l is unique up to unique isomorphism.

computer sciencecomputabilityprogram semantics

Source project: Lean Computer Science Library

Person-level attribution pending.

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Project-declaredLean 4.33.0-rc1

Buchi Family cover

Cslib.Automata.NA.Buchi.buchiFamily_cover

Project documentation

na.buchiFamily is a cover if na has only finitely many states. This theorem uses the Ramsey theorem for infinite graphs and does not depend on any details of na.BuchiCongruence other than that it is of finite index.

computer sciencecomputabilityprogram semantics

Source project: Lean Computer Science Library

Person-level attribution pending.

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