Algorithms for Bounding Folkman Numbers
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ABSTRACT
We write G -> (a1,...,ak)v
(G -> (a1,...,ak)e)
if for every vertex (edge) k-coloring of an undirected
simple graph G, a monochromatic Kai is
forced in color i ε {1,...,k}.
The vertex Folkman number is defined as
Fv(a1,...,ak;p) =
min{|V(G)| : G -> (a1,...,ak)v,
Kp ⊄ G}, p > max{a1,...,ak}.
Likewise, the edge Folkman number is defined as
Fe(a1,...,ak;p) =
min{|V(G)| : G -> (a1,...,ak)e,
Kp ⊄ G}, p > max{a1,...,ak}.
This thesis concerns the computation of a new result in
Folkman number theory, namely that Fv(2,2,3;4) = 14. Previously, the bounds stood at
10 ≤ Fv(2,2,3;4) ≤ 14, proven by Nenov in 2000. To achieve this new result,
specialized algorithms were executed on the computers
of the Computer Science network in a distributed processing effort.
We discuss the mathematics and algorithms used in the computation. We also
discuss ongoing research into the computation of the value of Fe(3,3;4);
the current bounds stand at 16 ≤ Fe(3,3;4) ≤ 3x109.
This number was once the subject of an Erdös prize—claimed by Spencer in
1988.