reserve T1,T2,T3 for TopSpace,
  A1 for Subset of T1, A2 for Subset of T2, A3 for Subset of T3;
reserve n,k for Nat;
reserve M,N for non empty TopSpace;
reserve p,q,p1,p2 for Point of TOP-REAL n;
reserve r for Real;

theorem Th16:
  k in Seg n implies (p1+p2).k = p1.k + p2.k
proof
A1: dom(p1+p2) = Seg n by FINSEQ_1:89;
  thus thesis by A1,VALUED_1:def 1;
end;
