64 citations · 139 across the 23 of their papers we have counts for
14 papers · 1 filter
On the Shannon capacity of sums and products of graphs
Alexander Schrijver
Let denote the Shannon capacity of a graph . We give an elementary proof of the equivalence, for any graphs and , of the inequalities and…
Semidefinite bounds for nonbinary codes based on quadruples
Bart Litjens, Sven Polak, Alexander Schrijver
For nonnegative integers , let denote the maximum cardinality of a code of length over an alphabet with letters and with minimum distance at least $…
Nullspace embeddings for outerplanar graphs
László Lovász, Alexander Schrijver
We study relations between geometric embeddings of graphs and the spectrum of associated matrices, focusing on outerplanar embeddings of graphs. For a simple connected graph $G=(V,…
The Strong Arnold Property for 4-connected flat graphs
Alexander Schrijver, Bart Sevenster
We show that if is a 4-connected flat graph, then any real symmetric matrix with exactly one negative eigenvalue and satisfying, for any two distinct vert…
Finding k partially disjoint paths in a directed planar graph
Alexander Schrijver
The {\it partially disjoint paths problem} is: {\it given:} a directed graph, vertices , and a set of pairs from , {\it find:}…
A Pythagoras proof of Szemerédi's regularity lemma
Alexander Schrijver
We give a short proof of Szemerédi's regularity lemma, based on elementary Euclidean geometry. The general line of the proof is that of the standard proof (in fact, of Szemerédi's…