Conflicts between ordered pairs
DefinitionEsgk_MatchingExtractionfinite-combinatoricsgraph-theory
This defines when two ordered pairs conflict by sharing an endpoint and provides the corresponding decidable relation.
Definition code
-- Extracted dependency interfaces and their necessary proofs.
import Definitions.Def_Esgk_DistanceDesign
import Mathlib
/-
Copyright (c) 2026 Adam McKenna. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Adam McKenna
-/
namespace Esgk
open EuclideanGeometry
variable {n : ℕ}
def OrderedPairConflict {V : Type*} (edge other : V × V) : Prop :=
edge.1 = other.1 ∨ edge.1 = other.2 ∨
edge.2 = other.1 ∨ edge.2 = other.2
instance instDecidableOrderedPairConflict {V : Type*} [DecidableEq V] :
DecidableRel (@OrderedPairConflict V) := by
intro edge other
unfold OrderedPairConflict
infer_instance
end Esgk