added cert_skolem; removed declare_thm; context: removed maxidx; added maxidx_of_pair for proper unification;
added cert_skolem;
removed declare_thm;
context: removed maxidx;
added maxidx_of_pair for proper unification;

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