the point-map of F .: K c= the Points of S2
proof
let b be object ; :: according to TARSKI:def 3 :: thesis: ( not b in the point-map of F .: K or b in the Points of S2 )
assume b in the point-map of F .: K ; :: thesis: b in the Points of S2
then ex a being object st
( a in dom the point-map of F & a in K & b = the point-map of F . a ) by FUNCT_1:def 6;
hence b in the Points of S2 by FUNCT_2:5; :: thesis: verum
end;
hence the point-map of F .: K is Subset of the Points of S2 ; :: thesis: verum