for W being Universe
for L being DOMAIN-Sequence of W st omega in W & ( for a, b being Ordinal of W st a in b holds
L . a c= L . b ) & ( for a being Ordinal of W st a <> {} & a is limit_ordinal holds
L . a = Union (L | a) ) & ( for a being Ordinal of W holds
( L . a in Union L & L . a is epsilon-transitive ) ) & Union L is closed_wrt_A1-A7 holds
Union L is being_a_model_of_ZF