5 papers
Lean-verified lower bounds for the Shannon capacity of odd cycles
Pjotr Buys, Sven Polak, Jeroen Zuiddam
We give new lower bounds for the Shannon capacities of small odd cycles: , , $Î(C_{13})\geq6.302455083464\ldot…
Semidefinite lower bounds for covering codes
Dion Gijswijt, Sven Polak
Let denote the minimum size of a -ary covering code of word length and covering radius . In other words, is the minimum size of a set of -ary cod…
Sum-of-squares certificates for symmetric polynomials on the hypercube: a counterexample to a conjecture of De Klerk and Laurent
Sven Polak
This paper studies sum-of-squares (SoS) representations of nonnegative polynomials over the hypercube . De Klerk and Laurent (SIAM J. Optim., 2010) conjectured that the sm…
Semidefinite and linear programming bounds for sum-rank-metric codes and non-existence results
Aida Abiad, Antonina P. Khramova, Sven C. Polak +1
The sum-rank metric provides a unifying framework that generalizes both the celebrated Hamming and rank metrics, and has found applications in areas such as network coding, distrib…
A group-theoretic approach to Shannon capacity of graphs and a limit theorem from lattice packings
Pjotr Buys, Sven Polak, Jeroen Zuiddam
We develop a group-theoretic approach to the Shannon capacity problem. Using this approach we extend and recover, in a structured and unified manner, various families of previously…