Attained signed duality for fractional triangle packings
OpenErdos81.fractional_triangle_signed_dualityEvery finite simple graph , including an edgeless graph, admits a feasible fractional triangle packing and a feasible signed triangle dual such that
Here is the number of unordered edges, the packing is nonnegative with total load at most one through each edge, and is the total signed edge weight. Dual feasibility requires an upper bound of one on each edge weight and on each triangle's total edge weight; negative edge weights are allowed.
The equality is the attained primal–dual certificate for the exact fractional partition problem with edge and triangle pieces. It provides the graph-specific interface between finite LP duality and chordal signed-weight estimates. No chordality or minimum-order hypothesis is required.
Formalization Note The platform already contains the proved general theorem SmaleNinth.lp_strong_duality. This target concerns its finite graph-incidence specialization, including the conversion to the existing packing representation.
import Definitions.Def_Erdos81_triangle_packings import Definitions.Def_Erdos81_signed_triangle_dual
theorem Erdos81.fractional_triangle_signed_duality {n : ℕ}
(G : SimpleGraph (Fin n)) :
∃ w y : Finset (Fin n) → ℝ,
Erdos81.IsFractionalTrianglePacking G w ∧
Erdos81.IsSignedTriangleDual G y ∧
(Erdos81.edgeCount G : ℝ) -
2 * Erdos81.fractionalTrianglePackingWeight w = Erdos81.signedEdgeWeight G y := by
sorry