defpred S₁[ Element of ] means ( $1 in A & (U_FT $1) \ {$1} misses A );
{ x where x is Element of : S₁[x] } is Subset of from DOMAIN_1:sch 7();
hence { x where x is Element of : ( x in A & (U_FT x) \ {x} misses A ) } is Subset of ; :: thesis: verum