theorem
 for I being non empty XFinSequence
 holds LastLoc I = card I - 1
proof let I be non empty XFinSequence;
A1:  card I >= 0+1 by NAT_1:13;
 thus LastLoc I = card I -' 1 by Th67
   .= card I - 1 by A1,XREAL_1:233;
end;
