theorem Th46:
  (i1 ';' i2 ';' i3 ';' i4).1 = IncAddr(i2,1)
 proof
  LastLoc(i1 ';' i2 ';' i3) = 3 by Th31;
  hence (i1 ';' i2 ';' i3 ';' i4).1 = (i1 ';' i2 ';' i3).1 by Th23,Th28
        .= IncAddr(i2,1) by Th45;
 end;
