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Project-declaredLean 4.24.0-rc1 · mathlib@aad26963

Acc omega lang inter2

Automata.acc_omega_lang_inter2

Plain-language statement

The ω-language accepted by the OI2 NA is the intersection of the ω-languages accepted by M0 and M1.

Exact Lean statement

theorem acc_omega_lang_inter2 :
    (NA.OI2 M acc).AcceptedOmegaLang (NA.OI2_Acc M acc) = ⋂ i : Fin 2, (M i).AcceptedOmegaLang (acc i)

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem acc_omega_lang_inter2 :    (NA.OI2 M acc).AcceptedOmegaLang (NA.OI2_Acc M acc) = ⋂ i : Fin 2, (M i).AcceptedOmegaLang (acc i) := by  ext as ; simp [NA.AcceptedOmegaLang, NA.BuchiAccept]  constructor  · rintro ss, h_run, h_inf i    have h_run1 := na_hist_inf_run_proj h_run    have h_run' := na_prod_inf_run.mp h_run1 i    use (fun k  (Prod.fst ∘ ss) k i) ; constructor    · assumption    let p0 k := ss k  { s | s.1 0  acc 0  s.2 = 0 }    let p1 k := ss k  { s | s.1 1  acc 1  s.2 = 1 }    have h_inf_or : ᶠ k in atTop, p0 k  p1 k := by exact h_inf    rw [frequently_or_distrib] at h_inf_or    let p0' k := (Prod.fst ∘ ss) k 0  acc 0    let p1' k := (Prod.fst ∘ ss) k 1  acc 1    have h_p0_p0' :  k, p0 k  p0' k := by intro k ; simp [p0, p0'] ; tauto    have h_p1_p1' :  k, p1 k  p1' k := by intro k ; simp [p1, p1'] ; tauto    revert i ; rw [Fin.forall_fin_two]    constructor <;> intro h_run_i    · rcases h_inf_or with h_inf0 | h_inf1      · exact Frequently.mono h_inf0 h_p0_p0'      · rw [ na_oi2_lemma1 M acc h_run] at h_inf1        exact Frequently.mono h_inf1 h_p0_p0'    · rcases h_inf_or with h_inf0 | h_inf1      · rw [na_oi2_lemma1 M acc h_run] at h_inf0        exact Frequently.mono h_inf0 h_p1_p1'      · exact Frequently.mono h_inf1 h_p1_p1'  · intro h_all    choose ss h_ss using h_all    let ss' := fun k i  ss i k    have h_ss' :  i, (M i).InfRun as (fun k  ss' k i) := by intro i ; exact (h_ss i).1    have h_run' := na_prod_inf_run.mpr h_ss'    have h_hist_init : NA.OI2_HistInit.Nonempty := by simp [NA.OI2_HistInit]    have h_hist_next :  s a, (NA.OI2_HistNext M acc s a).Nonempty := by      intro s a ; simp only [NA.OI2_HistNext]      rcases Classical.em (s.1 0  acc 0  s.2 = 0) with cond1 | cond1 <;> simp [cond1]      rcases Classical.em (s.1 1  acc 1  s.2 = 1) with cond2 | cond2 <;> simp [cond2]    have h_runh := na_hist_inf_run_exists h_hist_init h_hist_next h_run'    obtain hs, h_run := h_runh    use (fun k  (ss' k, hs k))    constructor    · assumption    have h_inf0 : ᶠ k in atTop, ss' k  { s | s 0  acc 0 } := by simp [ss', (h_ss 0).2]    have h_inf1 : ᶠ k in atTop, ss' k  { s | s 1  acc 1 } := by simp [ss', (h_ss 1).2]    exact na_oi2_lemma2 M acc h_run h_inf0 h_inf1
Project
Automata Theory
License
Apache-2.0
Commit
f196548710ce
Source
AutomataTheory/Automata/OI2.lean:140-184

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Person-level attribution pending.

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Plain-language statement

The language of the concatenation NA that is accepted by M1's accepting states is the language accepted by M0 concatenated with the language accepted by M1 minus the empty word.

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Source project: Automata Theory

Person-level attribution pending.

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