“…We observe anyhow, in this paper we applied an idea similar to [14] [15] [16] [18] [19], where, we modified the evolution equations obtaining equations with better symmetries, which incorporate the given equations. In this way, [14], [22], [23] , we preserve the contribution of some skewsymmetric terms, otherwise, if the initial evolution equations were used such contribution was null and, correspondingly, the stability criterion, weaker.…”