The induced Ramsey number of two finite simple
graphs is the least number of vertices in a graph
such that every red-blue coloring of the edges
of
contains a red induced subgraph isomorphic to
or a blue induced subgraph isomorphic to
. The copy must be induced in the entire
host graph
, and all its edges must have
the specified color. The host need not be a complete
graph. For complete graphs, this reduces to
the usual Ramsey number.
The Kohayakawa-Prömel-Rödl conjecture asserts a polynomial bound in the order
of
when
is fixed. Zhong et al. (2026) proved
for
and
.