2018/02/12 by Haviv, Ishay · 1 citation
#Combinatorics (math.CO) #Data Structures and Algorithms (cs.DS) #FOS: Computer and information sciences #FOS: Mathematics #Information Theory (cs.IT)
paper · doi:10.48550/arxiv.1802.03920
Two classical upper bounds on the Shannon capacity of graphs are the ϑ-function due to Lovász and the minrank parameter due to Haemers. We provide several explicit constructions of n-vertex graphs with a constant ϑ-function and minrank at least nδ for a constant δ>0 (over various prime order fields). This implies a limitation on the ϑ-function-based algorithmic approach to approximating the minrank parameter of graphs. The proofs involve linear spaces of multivariate polynomials and the method of higher incidence matrices.