
theorem Th1:
  for L being 1-sorted, C being trivial Subset of L, R being
  Relation of the carrier of L holds C is strict_chain of R
proof
  let L be 1-sorted, C be trivial Subset of L, R be Relation of the carrier of
  L;
  let x, y be set;
  thus thesis by SUBSET_1:def 7;
end;
