activity
20242026
collaborators

10 papers

math.CO2026

Canonical Ramsey theorem for graphs with clean intersections

Matías Azócar Carvajal, Ayush Basu, Christian Reiher +3

Extending earlier results of NeÅ¡etřil and Rödl [Selective graphs and hypergraphs, Ann. Discrete Math. 3 (1978), 181--189], we show that for every ordered graph there exist a…

math.CO2026

A lower bound on the Ramsey number

Pavel Pudlák, Vojtěch Rödl, William J. Wesley

We will prove that , where is the tower function defined by and . We also give pro…

math.CO2026

On Ramsey number of Steiner systems

Ayush Basu, Daniel Dobak, Vojtěch Rödl +1

A -uniform hypergraph is called a partial -system if every set of vertices of is contained in at most one edge of . We prove the existence of a pa…

math.CO2025

Nowhere dense Ramsey sets

Vojtěch Rödl, Marcelo Sales

A set of points in Euclidean space is called \textit{Ramsey} if any finite partition of yields a monochromatic copy of . While character…

math.CO2025

Unavoidable subgraphs in Ramsey graphs

Christian Reiher, Vojtěch Rödl, Mathias Schacht

We study subgraphs that appear in large Ramsey graphs for a given graph . The recent girth Ramsey theorem of the first two authors asserts that there are Ramsey graphs such that…

math.CO2025

Ramsey-type problems for generalised Sidon sets

Christian Reiher, Vojtěch Rödl, Mathias Schacht

We establish the existence of generalised Sidon sets enjoying additional Ramsey-type properties, which are motivated by questions of Erdős and Newman and of Alon and Erdős.