Images of contractive projections on operator algebras

It is shown that if P is a weak∗-continuous contractive projection on a JBW∗-triple M, then P(M) is of type I or semifinite, respectively, if M is of the corresponding type. We also show that P(M) has no infinite spin part if M is a type I von Neumann algebra.  2002 Elsevier Science (USA). All rights reserved.