deleted a reference to "nat", now erroneous because "nat" is a function
deleted a reference to "nat", now erroneous because "nat" is a function

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