code: public static <G extends Relatable<?>> Context downset(final CompleteLattice lattice) {
          List<Object> elements = Arrays.asList(lattice.toArray());
          return new Context(elements, elements, new NotGreaterOrEqual());
      }
docs: Calculate the isomorphic downset lattice.
  @param <G> element type
  @param lattice of elements
  @return the downset lattice of a given complete lattice