:The source is a dictionary of theological / doctrinal terms.  The text is from the entry on purgatory.  It says "Greek authors like [examples] and Latin authors like [examples] wrote in various ways of purification after death and our comunion through prayer with our dead departed".  Purgatory is purification.  If you says "the dead may be purified" then you have said a statement about purgatory.  The authors in question say, according to the source(s), that the dead may be purified and prayer is involved.  The authors coupled purification of the dead and prayer for the dead, so we are right to say as much.  As yet I do not think we have a very solid source on EoC belief, but it doesnt seem relevant here.