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Project-declaredLean 4.33.0-rc1 · mathlib@169c26b52a38

Loop run exists

Cslib.Automata.NA.loop_run_exists

Plain-language statement

For any infinite sequence xls of nonempty finite words from language na, there is an infinite run of na.loop corresponding to xls.flatten in which the state () marks the boundaries between the finite words in xls.

Exact Lean statement

theorem loop_run_exists [Inhabited Symbol] {xls : ωSequence (List Symbol)}
    (h : ∀ k, (xls k) ∈ language na - 1) :
    ∃ ss, na.loop.Run xls.flatten ss ∧ ∀ k, ss (xls.cumLen k) = inl ()

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem loop_run_exists [Inhabited Symbol] {xls : ωSequence (List Symbol)}    (h :  k, (xls k)  language na - 1) :     ss, na.loop.Run xls.flatten ss   k, ss (xls.cumLen k) = inl () := by  let ts := ωSequence.const (inl () : UnitState)  have h_mtr (k : ) : na.loop.MTr (ts k) (xls k) (ts (k + 1)) := by grind [loop_fin_run_mtr]  have (k : ) : xls k  [] := by grind  have h_pos (k : ) : (xls k).length > 0 := List.length_pos_iff.mpr (this k)  obtain ss, _, _ := LTS.OmegaExecution.flatten_mTr h_mtr h_pos  use ss  grind [Run.mk, FinAcc.loop, cumLen_zero (ls := xls)]
Project
Lean Computer Science Library
License
Apache-2.0
Commit
f36649cff2c9
Source
Cslib/Computability/Automata/NA/Loop.lean:126-135

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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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