
Hajnal, Andras
Multicolour Erdős--Hajnal Conjecture ★★★
Conjecture For every fixed
and fixed colouring
of
with
colours, there exists
such that every colouring of the edges of
contains either
vertices whose edges are coloured according to
or
vertices whose edges are coloured with at most
colours.










Keywords: ramsey theory
Unions of triangle free graphs ★★★
Problem Does there exist a graph with no subgraph isomorphic to
which cannot be expressed as a union of
triangle free graphs?


Keywords: forbidden subgraph; infinite graph; triangle free
The Erdös-Hajnal Conjecture ★★★
Conjecture For every fixed graph
, there exists a constant
, so that every graph
without an induced subgraph isomorphic to
contains either a clique or an independent set of size
.





Keywords: induced subgraph
