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Project-declaredLean 4.33.0-rc1 · mathlib@169c26b52a38

Relates In Steps iff configs eq

Turing.MultiTapeTM.relatesInSteps_iff_configs_eq

Project documentation

This lemma translates between the relational notion and the iterated step notion. The latter can be more convenient especially for deterministic machines as we have here.

Exact Lean statement

@[scoped grind =]
lemma relatesInSteps_iff_configs_eq
    (tm : MultiTapeTM k Symbol State)
    (cfg₁ cfg₂ : Cfg k Symbol State input)
    (t : ℕ) :
    RelatesInSteps tm.TransitionRelation cfg₁ cfg₂ t ↔ tm.configs cfg₁ t = cfg₂

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
@[scoped grind =]lemma relatesInSteps_iff_configs_eq    (tm : MultiTapeTM k Symbol State)    (cfg₁ cfg₂ : Cfg k Symbol State input)    (t : ) :    RelatesInSteps tm.TransitionRelation cfg₁ cfg₂ t  tm.configs cfg₁ t = cfg₂ := by  unfold configs  induction t generalizing cfg₁ cfg₂ with  | zero => simp  | succ t ih =>    rw [RelatesInSteps.succ_iff, Function.iterate_succ_apply']    constructor    · grind    · intro h_configs      use tm.step^[t] cfg₁      grind
Project
Lean Computer Science Library
License
Apache-2.0
Commit
f36649cff2c9
Source
Cslib/Computability/Machines/Turing/MultiTape/Deterministic.lean:431-446

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Related declarations

Project-declaredLean 4.33.0-rc1

Unique minimal

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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

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computer sciencecomputabilityprogram semantics

Source project: Lean Computer Science Library

Person-level attribution pending.

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