more aggressive nested size handling in the absence of 'size_o_map' theorems (+ unrelated pattern matching fix)
more aggressive nested size handling in the absence of 'size_o_map' theorems (+ unrelated pattern matching fix)

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