let H be ZF-formula; :: thesis: ( H is conjunctive implies H = (the_left_argument_of H) '&' (the_right_argument_of H) )
assume A1: H is conjunctive ; :: thesis: H = (the_left_argument_of H) '&' (the_right_argument_of H)
then ex F1 being ZF-formula st H = (the_left_argument_of H) '&' F1 by Def31;
hence H = (the_left_argument_of H) '&' (the_right_argument_of H) by A1, Def32; :: thesis: verum