19 citations · 41 across the 9 of their papers we have counts for
8 papers · 1 filter
Inhomogeneous Partition Regularity
Imre Leader, Paul A. Russell
We say that the system of equations , where is an integer matrix and is a (non-zero) integer vector, is partition regular if whenever the integers are finitely colour…
Monochromatic infinite sumsets
Imre Leader, Paul A. Russell
We show that there is a rational vector space such that, whenever is finitely coloured, there is an infinite set whose sumset is monochromatic. Our example is the…
Set Systems Containing Many Maximal Chains
J. Robert Johnson, Imre Leader, Paul A. Russell
The purpose of this short problem paper is to raise an extremal question on set systems which seems to be natural and appealing. Our question is: which set systems of a given size…
Probably Intersecting Families are Not Nested
Paul A. Russell, Mark Walters
It is well known that an intersecting family of subsets of an n-element set can contain at most 2^(n-1) sets. It is natural to wonder how `close' to intersecting a family of size g…
Compressions and Probably Intersecting Families
Paul A. Russell
A family X of sets is said to be intersecting if any two members of X have non-empty intersection. It is a well-known and simple fact that an intersecting family of subsets of [n]=…
Transitive Sets and Cyclic Quadrilaterals
Imre Leader, Paul A. Russell, Mark Walters
Motivated by some questions in Euclidean Ramsey theory, our aim in this note is to show that there exists a cyclic quadrilateral that does not embed into any transitive set (in any…
Transitive Sets in Euclidean Ramsey Theory
Imre Leader, Paul A. Russell, Mark Walters
A finite set in some Euclidean space is called Ramsey if for any there is a such that whenever is -coloured it contains a monochromatic set congruent to…
Families intersecting on an interval
Paul A. Russell
We shall be interested in the following Erdos-Ko-Rado-type question. Fix some subset B of [n]. How large a family A of subsets of [n] can we find such that the intersection of any…