In Lemma 2.4, the equalities in (2.7) and should be deleted. Before Lemma 2.4, the following statement should be added.

Following the main idea of the proofs of Theorems 2.1 and 3.1 in [1], we can derive the following lemma over .

The original Lemma 2.4 should be replaced by the following.

Lemma 2.4. Let , , and be given; if is contained in , then