theorem Th49:
  loc in dom I implies Shift(stop I,n).(loc+n)=Shift(I,n).(loc+n)
proof
A1: dom I c= dom (stop I) by AFINSQ_1:21;
  reconsider l = loc as Element of NAT by ORDINAL1:def 12;
  assume
A2: loc in dom I;
  hence Shift(I,n).(loc+n)=I.l by VALUED_1:def 12
    .=(stop I).l by A2,AFINSQ_1:def 3
    .=Shift(stop I,n).(loc+n) by A2,A1,VALUED_1:def 12;
end;
