8 papers · 1 filter
An improved algebraic construction for Ramsey numbers
Ferdinand Ihringer, Sam Mattheus
We provide an explicit algebraic construction showing that, uniformly for integers , as , \[ R( s,t ) \geq t^{(1-o(1)) \log s / \log(\log s + 1) }. \…
A note on the classification of classical distance-regular graphs of negative type and the non-existence of hemisystems
Sam Adriaensen, Jan De Beule, Jozefien D'haeseleer +1
DISCLAIMER: Due to an error in the literature, we cannot be sure that the conclusions drawn in this paper are correct. The goal of this note is to connect some interesting results…
Improved bounds for the minimum degree of minimal multicolor Ramsey graphs
Yamaan Attwa, Sam Mattheus, Tibor Szabó +1
We provide two novel constructions of edge-disjoint -free graphs on the same vertex set, each of which has the property that every small induced subgraph contains a co…
The largest sets of non-opposite chambers in spherical buildings of type
Jan De Beule, Philipp Heering, Sam Mattheus +1
The investigation into large families of non-opposite flags in finite spherical buildings has been a recent addition to a long line of research in extremal combinatorics, extending…
Larger Nearly Orthogonal Sets over Finite Fields
Ishay Haviv, Sam Mattheus, Aleksa MilojeviÄ +1
For a field and integers and , a set is called -nearly orthogonal if its members are non-self-orthogonal and every ve…
Off-diagonal Ramsey numbers for slowly growing hypergraphs
Sam Mattheus, Dhruv Mubayi, Jiaxi Nie +1
For a -uniform hypergraph and a positive integer , the Ramsey number denotes the minimum such that every -vertex -free -uniform hypergraph contains…