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LeanPool.CencovPetz.ContinuousExtension

CencovPetz.ContinuousExtension #

Reusable “extend equality from a dense set” lemmas for functions on the finite open simplex.

This is used in the last step of the finite Čencov/Chentsov argument: once an identity is shown on a dense family of rational/common-denominator points, continuity hypotheses allow extending the identity to all simplex points.

Main result #

theorem LeanPool.CencovPetz.eq_of_eqOn_dense₂ {α : Type u} [Fintype α] {s : Set (Simplex α)} (hs : Dense s) {f g : Simplex α(tangentSpace α)(tangentSpace α)} (hf : ∀ (u v : (tangentSpace α)), Continuous fun (p : Simplex α) => f p u v) (hg : ∀ (u v : (tangentSpace α)), Continuous fun (p : Simplex α) => g p u v) (hfg : ps, ∀ (u v : (tangentSpace α)), f p u v = g p u v) (p : Simplex α) (u v : (tangentSpace α)) :
f p u v = g p u v