begin
:: deftheorem Def1 defines order-sorted OSALG_3:def 1 :
theorem
canceled;
theorem Th2:
theorem Th3:
theorem
theorem Th5:
theorem Th6:
theorem Th7:
theorem Th8:
:: deftheorem Def2 defines are_os_isomorphic OSALG_3:def 2 :
theorem Th9:
theorem Th10:
theorem
theorem Th12:
theorem Th13:
theorem Th14:
theorem Th15:
theorem Th16:
theorem
theorem
theorem