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https://github.com/saymrwulf/ltl-accumulator-verified.git
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28 lines
1.1 KiB
Text
28 lines
1.1 KiB
Text
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/- S5.3 Fable re-audit artifact (permanent, not a throwaway probe): the
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S5.3 change of ConsRec's base from list-match to decidable `if` must be
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SEMANTICS-PRESERVING — Opus's only evidence was "the chain recompiled".
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These two theorems machine-check the equivalence against the exact
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list-match forms that were replaced, so the refactor's faithfulness is
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a permanent, cone-audited guarantee. -/
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import Proofs.Basic
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namespace LTLAcc
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/-- b=false base: decidable-if form = the original `[s]` list-match. -/
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theorem consRec_base_false_eq (C : List Hash) :
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(if C.length = 1 then some ((C.getLastD default, C.getLastD default) : Hash × Hash) else none)
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= (match C with | [s] => some (s, s) | _ => none) := by
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cases C with
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| nil => rfl
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| cons a t => cases t with | nil => rfl | cons b u => simp
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/-- b=true base: decidable-if form = the original `[]` list-match. -/
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theorem consRec_base_true_eq (C : List Hash) (r : Hash) :
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(if C = [] then some ((r, r) : Hash × Hash) else none)
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= (match C with | [] => some (r, r) | _ => none) := by
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cases C with
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| nil => rfl
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| cons a t => rfl
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end LTLAcc
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