Wing-triangulated graphs are perfect

The wing-graph W(G) of a graph G has all edges of G as its vertices; two edges of G are adjacent in W(G) if they are the nonincident edges (called wings) of an induced path on four vertices in G. Hoang conjectured that if W(G) has no induced cycle of odd length at least five, then G is perfect. As a partial result towards Hoang's conjecture we prove that if W(G) is triangulated, then G is perfect. (C) 1997 John Wiley & Sons, Inc.