theorem
  for s being SCM-State of G, t being Element of SCM-Data-Loc, u being
  Element of G holds SCM-Chg(s,t,u).t = u
proof
  let s be SCM-State of G, t be Element of SCM-Data-Loc, u be Element of G;
  t in dom(t .--> u) by TARSKI:def 1;
  hence SCM-Chg(s,t,u).t = (t .--> u).t by FUNCT_4:13
    .= u by FUNCOP_1:72;
end;
