reserve n for Nat,
  k for Integer;
reserve p for polyhedron,
  k for Integer,
  n for Nat;

theorem Th65:
  [#](dim(p)-chain-space(p)) = { 0.(dim(p)-chain-space(p)), {p} }
proof
  set V = dim(p)-chain-space(p);
  set C = [#]V;
A1: card C = 2 by Th61;
  reconsider C as finite set;
A2: {p} in C by Th63;
  ex a,b being object st a <> b & C = {a,b} by A1,CARD_2:60;
  hence thesis by A2,Th1;
end;
