theorem Th68:
  A is elementary implies
  for a being SortSymbol of S
  for x being Element of (the generators of G).a
  for t being Element of T,a holds
  x:=(t,A) in ElementaryInstructions A
  proof assume
A1: rng the assignments of A c= ElementaryInstructions A;
    let a be SortSymbol of S;
    let x be Element of (the generators of G).a;
    let t be Element of T,a;
    [x,t] in [:(the generators of G).a,(the Sorts of T).a:] by ZFMISC_1:87;
    then [x,t] in [|the generators of G, the Sorts of T|].a &
    dom [|the generators of G, the Sorts of T|] = the carrier of S
    by PARTFUN1:def 2,PBOOLE:def 16;
    then x:=(t,A) in rng the assignments of A by FUNCT_2:4,CARD_5:2;
    hence thesis by A1;
   end;
