reserve n for Nat;

theorem lemacf5:
for R being domRing,
    B being non zero bag of the carrier of R
for p being Ppoly of R,B holds deg p = card BRoots p
proof
let R be domRing, B be non zero bag of the carrier of R;
let p be Ppoly of R,B;
thus card(BRoots p) = card B by pf2 .= deg p by dpp;
end;
