
theorem Th32:
  for T being _Tree, a, b being Vertex of T holds T.pathBetween(a,
  b).vertices() = T.pathBetween(b,a).vertices()
proof
  let T be _Tree, a, b be Vertex of T;
  T.pathBetween(a,b).reverse() = T.pathBetween(b,a) by Th31;
  hence thesis by GLIB_001:92;
end;
