removed redundant ball_empty and bex_empty (see equalities.ML)
removed redundant ball_empty and bex_empty (see equalities.ML)

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