proof

P25A

Lean spine source

Declarations: amplification_not_correction_contraction

From the machine-checked spine in formal/ (Mathlib + spine imports). Not self-contained for Lean 4 Web — use the repo or a local lake build.

theorem amplification_not_correction_contraction :
    ∃ a : Bool, ToyLocalRecursiveSupervision a ∧ ¬ ToyCorrectionContraction a :=
  ⟨false, trivial, by decide⟩