Everett–Reed's conjecture on even-contractile Berge graphs

Let $G$ be a Berge graph, meaning a graph with no induced odd hole and no induced odd antihole. An antihole is the complement of a hole, and an odd prism is a prism whose three rungs all have an odd number of edges. A graph is even-contractile if it can be reduced to a single vertex by contracting edges whose endpoints have no common neighbor. Everett–Reed's conjecture. If $G$ has no induced subgraph isomorphic to an antihole of length at least six or to an odd prism, then $G$ is even-contractile. This conjecture concerns a proposed characterization of even-contractile Berge graphs and remains open, although several related theorems have been proved.