reserve n for Nat;

theorem
for R being domRing, a being Element of R holds LC(a|R) = a
proof
let R be domRing, a be Element of R;
thus LC(a|R) = LC(a*(1_.(R))) by RING_4:16
            .= a * LC(1_.(R)) by prl0a
            .= a * 1.R by RATFUNC1:def 7
            .= a;
end;
