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;
reserve i,j for natural Number;
reserve F for Function of [:D,D9:],E;
reserve p,q for FinSequence of D,
  p9,q9 for FinSequence of D9;
reserve f,f9 for Function of C,D,
  h for Function of D,E;
reserve T,T1,T2,T3 for Tuple of i,D;
reserve T9 for Tuple of i, D9;
reserve S for Tuple of j, D;
reserve S9 for Tuple of j, D9;

theorem
  F[;](d,T9) = F[;](d,id D9)*T9
proof
  rng T9 c= D9;
  hence F[;](d,T9) = F[;](d,(id D9)*T9) by RELAT_1:53
    .= F[;](d,(id D9))*T9 by FUNCOP_1:34;
end;
