let M be non empty set ; ( M |= ZF-axioms & M is epsilon-transitive implies M is being_a_model_of_ZF )
the_axiom_of_power_sets in WFF
by ZF_LANG:4;
then A1:
the_axiom_of_power_sets in ZF-axioms
by Def4;
the_axiom_of_infinity in WFF
by ZF_LANG:4;
then A2:
the_axiom_of_infinity in ZF-axioms
by Def4;
the_axiom_of_unions in WFF
by ZF_LANG:4;
then A3:
the_axiom_of_unions in ZF-axioms
by Def4;
assume that
A4:
for H being ZF-formula st H in ZF-axioms holds
M |= H
and
A5:
M is epsilon-transitive
; ZFREFLE1:def 1 M is being_a_model_of_ZF
the_axiom_of_pairs in WFF
by ZF_LANG:4;
then
the_axiom_of_pairs in ZF-axioms
by Def4;
hence
( M is epsilon-transitive & M |= the_axiom_of_pairs & M |= the_axiom_of_unions & M |= the_axiom_of_infinity & M |= the_axiom_of_power_sets )
by A4, A5, A3, A2, A1; ZF_MODEL:def 12 for b1 being M8( omega ) holds
( not {(x. 0),(x. 1),(x. 2)} misses Free b1 or M |= the_axiom_of_substitution_for b1 )
let H be ZF-formula; ( not {(x. 0),(x. 1),(x. 2)} misses Free H or M |= the_axiom_of_substitution_for H )
assume A6:
{(x. 0),(x. 1),(x. 2)} misses Free H
; M |= the_axiom_of_substitution_for H
the_axiom_of_substitution_for H in WFF
by ZF_LANG:4;
then
the_axiom_of_substitution_for H in ZF-axioms
by A6, Def4;
hence
M |= the_axiom_of_substitution_for H
by A4; verum