Hastriangletightness of incidence square
ProvedConway99Formal.CubicOperators.Graph.hasTriangleTightness_of_incidence_squaregraph-theorylinear-algebra
For a finite graph with a point frame and the stated incidence-matrix square identity, its triangle vectors satisfy the frame tightness identity.
Preamble
import Definitions.Def_CubicOperators
import Mathlib
namespace Conway99Formal.CubicOperators.Graph
end Conway99Formal.CubicOperators.Graph
set_option autoImplicit false
/-! Algebraic contraction lemmas for the graph-owned triangle cubic. The
incidence identities in the hypotheses are the explicit graph bridge. -/
open Conway99Formal.CubicOperators
open Finset
variable {T I : Type*} [Fintype T] [Fintype I]
open Conway99Formal.CubicOperators.Graph
open Finset
variable {V : Type*} [Fintype V] [DecidableEq V]
variable (G : SimpleGraph V) [DecidableRel G.Adj]
Formal statement
theorem Conway99Formal.CubicOperators.Graph.hasTriangleTightness_of_incidence_square (Pi : Matrix Coord V ℝ)
(hf : IsPointFrame G Pi)
(hinc : realIncidenceMatrix G * (realIncidenceMatrix G).transpose =
7 • (1 : Matrix V V ℝ) + G.adjMatrix ℝ) :
HasTriangleTightness G Pi := by sorry
Source
blob/a45708acebe3f397faccb1b646be906f24f23ee5/formalization/2026-10-03/cubic-operators/CubicOperators.lean#L722-L772