Xu, Ling
Cao, Tingbin http://orcid.org/0000-0003-3284-9730
Funding for this research was provided by:
National Natural Science Foundation of China (11461042)
Article History
Received: 5 March 2018
Accepted: 13 November 2018
First Online: 21 November 2018
Change Date: 4 December 2019
Change Type: Correction
Change Details: We give a correction to Theorem 1.2 in a previous paper [Mediterr. J. Math. (2018) 15:227]. Two examples are given to explain the corrected conclusion.