Resolutions of generalized polyhedral manifolds
Gerald A. Anderson · Tohoku Mathematical Journal · 1979
LEMMA 1.1.// Λf α^d N are PL J^-manifolds with collared boundaries, then M x N is a PL ^manifold with boundary M x 3JV U 3M x N.PROOF.Let (x, y)eM x JV.Thenand is in &~ if a? ί 3ikί, ygdN by condition (iii) above.If x e dM, then