reserve x,y,X,Y for set;
reserve C for non empty set;
reserve c for Element of C;
reserve f,f1,f2,f3,g,g1 for PartFunc of C,COMPLEX;
reserve r1,r2,p1 for Real;
reserve r,q,cr1,cr2 for Complex;

theorem Th42:
  (f1/f2)^ = (f2|dom(f2^))/f1
proof
  thus (f1/f2)^ = (f1(#)(f2^))^ by Th38
    .= (f1^)(#)(f2^^) by Th34
    .= (f2|dom(f2^))(#)(f1^) by Th33
    .= (f2|dom(f2^))/f1 by Th38;
end;
