theorem Th26:
  B is quantifiable implies Sub_All(B,SQ)`1 = All(B`2,(B`1)`1) &
  Sub_All(B,SQ)`2 = SQ
proof
  assume B is quantifiable;
  then Sub_All(B,SQ) = [All(B`2,(B`1)`1),SQ] by SUBSTUT1:def 24;
  hence thesis;
end;
