reserve x,y for set;
reserve C,C9,D,D9,E for non empty set;
reserve c for Element of C;
reserve c9 for Element of C9;
reserve d,d1,d2,d3,d4,e for Element of D;
reserve d9 for Element of D9;

theorem Th7:
  for F being Function, X being set, x1,x2 being set st
    [x1,x2] in dom F holds F.:(X-->x1,X-->x2) = X --> F.(x1,x2)
proof
  let F be Function, X be set, x1,x2 be set such that
A1: [x1,x2] in dom F;
  set f = X-->x1, g = X-->x2;
  thus F.:(f,g) = F*(X-->[x1,x2]) by Th6
    .= X --> F.(x1,x2) by A1,FUNCOP_1:17;
end;
