reserve k,n for Nat,
  x,y,z,y1,y2 for object,X,Y for set,
  f,g for Function;
reserve p,q,r,s,t for XFinSequence;
reserve D for set;
reserve i for Nat;
reserve m for Nat,
        D for non empty set;
reserve l for Nat;
reserve M for Nat;
reserve m,n for Nat;
reserve x1,x2,x3,x4 for object;
reserve e,u for object;

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;
