discontinued home-made sharing for proof terms -- leave memory management to the Poly/ML RTS;
discontinued home-made sharing for proof terms -- leave memory management to the Poly/ML RTS;

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