Added an equivalence proof which avoids the use of -n-> (with help from Ranan Fraer)
Added an equivalence proof which avoids the use of -n->
(with help from Ranan Fraer)

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle