English

Affine maps between quadratic assignment polytopes and subgraph isomorphism polytopes

Computational Complexity 2017-06-20 v3 Discrete Mathematics Combinatorics Optimization and Control

Abstract

We consider two polytopes. The quadratic assignment polytope QAP(n)QAP(n) is the convex hull of the set of tensors xxx\otimes x, xPnx \in P_n, where PnP_n is the set of n×nn\times n permutation matrices. The second polytope is defined as follows. For every permutation of vertices of the complete graph KnK_n we consider appropriate (n2)×(n2)\binom{n}{2} \times \binom{n}{2} permutation matrix of the edges of KnK_n. The Young polytope P((n2,2))P((n-2,2)) is the convex hull of all such matrices. In 2009, S. Onn showed that the subgraph isomorphism problem can be reduced to optimization both over QAP(n)QAP(n) and over P((n2,2))P((n-2,2)). He also posed the question whether QAP(n)QAP(n) and P((n2,2))P((n-2,2)), having n!n! vertices each, are isomorphic. We show that QAP(n)QAP(n) and P((n2,2))P((n-2,2)) are not isomorphic. Also, we show that QAP(n)QAP(n) is a face of P((2n2,2))P((2n-2,2)), but P((n2,2))P((n-2,2)) is a projection of QAP(n)QAP(n).

Cite

@article{arxiv.1705.10081,
  title  = {Affine maps between quadratic assignment polytopes and subgraph isomorphism polytopes},
  author = {Aleksandr Maksimenko},
  journal= {arXiv preprint arXiv:1705.10081},
  year   = {2017}
}

Comments

6 pages, translated to English

R2 v1 2026-06-22T20:01:56.465Z