From ea38ef0cb2c57e10696c7fb6108732a6f454818c Mon Sep 17 00:00:00 2001 From: Hannes Schulze Date: Thu, 20 Nov 2025 11:56:18 +0100 Subject: wip terms --- Nominal/Instances/Basic.lean | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Nominal/Instances/Basic.lean') diff --git a/Nominal/Instances/Basic.lean b/Nominal/Instances/Basic.lean index d41e87f..dea5bcf 100644 --- a/Nominal/Instances/Basic.lean +++ b/Nominal/Instances/Basic.lean @@ -282,6 +282,11 @@ lemma supp {x : X} : NominalSet.supp 𝔸 (Quotient.mk setoid.toSetoid x) = {a | simp only [FPerm.swap_inv, PermSet.atom_swap, Equiv.swap_apply_left] exact hc.right +/-- If an atom is not in the support of the equivalence class, one can always pick a representative where it is not in the least support. -/ +lemma supp_pick_fresh {a : 𝔸} {x : X} : a ∉ NominalSet.supp 𝔸 (Quotient.mk setoid.toSetoid x) → ∃ (y : X), y ≈ x ∧ a ∉ NominalSet.supp 𝔸 y := by + contrapose + simp [not_exists, not_and, not_not, supp] + end Quotient end Quotient -- cgit v1.3.1