3 citations · 5 across the 2 of their papers we have counts for
9 papers · 1 filter
New small regular graphs of given girth: the cage problem and beyond
Geoffrey Exoo, Jan Goedgebeur, Jorik Jooken +2
The cage problem concerns finding -graphs, which are -regular graphs with girth , of the smallest possible number of vertices. The central goal is to determine $n(k,g)…
A Lower Bound for R(5,6)
Geoffrey Exoo
The known lower bound for the the classical Ramsey number is improved from to . The method used to construct the graph is a simple variant of computational method…
Attainable bounds for algebraic connectivity and maximally-connected regular graphs
Geoffrey Exoo, Theodore Kolokolnikov, Jeanette Janssen +1
We derive attainable upper bounds on the algebraic connectivity (spectral gap) of a regular graph in terms of its diameter and girth. This bound agrees with the well-known Alon-Bop…
On large regular (1,1,k)-mixed graphs
C. Dalfó, G. Erskine, G. Exoo +4
An -mixed graph has every vertex with undirected degree , directed in- and out-degree , and diameter . In this paper, we study the case , proposing som…
A 5-chromatic same-distance graph in the hyperbolic plane
Geoffrey Exoo, Dan Ismailescu
The chromatic number of the plane problem asks for the minimum number of colors so that each point of the plane can be assigned a single color with the property that no two points…
The chromatic number of the Minkowski plane -- the regular polygon case
Geoffrey Exoo, David Fisher, Dan Ismailescu
The Hadwiger-Nelson problem asks for the minimum number of colors, so that each point of the plane can be assigned a single color with the property that no two points unit-distance…