const SNo_pair : set set set const minus_SNo : set set term - = minus_SNo const CSNo_Re : set set const CSNo_Im : set set term minus_CSNo = \x:set.SNo_pair (- CSNo_Re x) - CSNo_Im x const In : set set prop term iIn = In infix iIn 2000 2000 const complex : set const real : set axiom complex_Re_real: !x:set.x iIn complex -> CSNo_Re x iIn real axiom real_minus_SNo: !x:set.x iIn real -> - x iIn real axiom complex_Im_real: !x:set.x iIn complex -> CSNo_Im x iIn real axiom complex_I: !x:set.x iIn real -> !y:set.y iIn real -> SNo_pair x y iIn complex claim !x:set.x iIn complex -> minus_CSNo x iIn complex