reserve P for Subset of TOP-REAL 2,
  f,f1,f2,g for FinSequence of TOP-REAL 2,
  p,p1,p2,q,q1,q2 for Point of TOP-REAL 2,
  r1,r2,r19,r29 for Real,
  i,j,k,n for Nat;

theorem
  p in LSeg(f,i) implies p in L~f
proof
  LSeg(f,i) c= L~f by TOPREAL3:19;
  hence thesis;
end;
