About the Authors

Lei Ren

Roles Funding acquisition, Methodology, Writing – original draft, Writing – review & editing

renqihan@hotmail.com

Affiliation School of Mathematics and Statistics, Shangqiu Normal University, Shangqiu, Henan, People’s Republic of China

Shixin Jin

Roles Data curation, Funding acquisition

Affiliation School of Mathematics and Statistics, Shangqiu Normal University, Shangqiu, Henan, People’s Republic of China

Competing Interests

The authors have declared that no competing interests exist.