Proof of `Positive Ehrenfeucht–Fraïssé games` (2nd statement)

groundedproofs/Lax503819Proofs/Games.lean · lax-503819

What this proof establishes

no assumptions

Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.

Read the Lean proof on GitHub

Description

The word specialization of Theorem 5.7 (and hence Theorem 3.7). Soundness is induction on formulas; completeness combines finitely many separating formulas, one per possible response in the other finite word.