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JOURNALS // Fundamentalnaya i Prikladnaya Matematika // Archive

Fundam. Prikl. Mat., 2013 Volume 18, Issue 2, Pages 95–103 (Mi fpm1501)

This article is cited in 5 papers

$k$-neighborly faces of the Boolean quadric polytopes

A. N. Maksimenko

P. G. Demidov Yaroslavl State University, Yaroslavl, Russia

Abstract: The Boolean quadric polytope (or correlation polytope) is the convex hull
$$ \operatorname{BQP}(n)=\operatorname{conv}\{x=(x_{ij})\in\{0,1\}^{n(n+1)/2}\mid x_{ij}=x_{ii}x_{jj},\ 1\le i\le j\le n\}. $$
The number of its vertices is $2^n$, i.e., superpolynomial in the dimension $d=n(n+1)/2$. In 1992 M. Deza, M. Laurent, and S. Poljak proved that $\operatorname{BQP}(n)$ is $3$-neighborly, i.e., every three vertices of $\operatorname{BQP}(n)$ form a face of this polytope. By analogy with the Boolean quadric polytopes, we consider Boolean $p$-power polytopes $\operatorname{BQP}(n,p)$. For $p=2$, $\operatorname{BQP}(n,p)=\operatorname{BQP}(n)$. For $p=1$, $\operatorname{BQP}(n,p)$ is $n$-dimensional $0/1$-cube. It is shown that $\operatorname{BQP}(n,p)$ is $s$-neighborly for $s\le p+\lfloor p/2\rfloor$. For $k\ge2m$, $m\in\mathbb N$, we prove that the polytope $\operatorname{BQP}(k,2m)$ is linearly isomorphic to a face of $\operatorname{BQP}(n)$ for some $n=\Theta\left(\binom km\right)$. Hence, for every fixed $s\le3\lfloor\log_2 n/2\rfloor$, $\operatorname{BQP}(n)$ has $s$-neighborly face with superpolynomial number $2^{\Theta(n^{1/\lceil s/3\rceil})}$ of vertices.

UDC: 519.854.33+514.172.45


 English version:
Journal of Mathematical Sciences (New York), 2014, 203:6, 816–822

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