begin
:: deftheorem Def1 defines Collapse ZF_COLLA:def 1 :
theorem Th1:
theorem
theorem
theorem Th4:
theorem Th5:
theorem Th6:
theorem Th7:
theorem Th8:
theorem Th9:
:: deftheorem defines is_epsilon-isomorphism_of ZF_COLLA:def 2 :
:: deftheorem defines are_epsilon-isomorphic ZF_COLLA:def 3 :
theorem
canceled;
theorem
canceled;
theorem Th12:
theorem Th13:
theorem