| Affiliation: | 1. Department of Mathematics, Whitman College, 63 Wolf Fock Place, Walla Walla, WA 99362, USA;2. Dipartimento di Matematica “Tullio Levi-Civita”, Università di Padova, Via Trieste 63, 35121 Padova, Italy;1. Charlotte Scott Research Centre for Algebra, University of Lincoln, UK;2. Sobolev Institute of Mathematics, Novosibirsk, 630090, Russia;3. Departament de Matemàtiques, Universitat de València, 46100, Burjassot, València, Spain;4. Department of Mathematics, University of Kurdistan, P.O. Box: 416, Sanandaj, Iran;1. Department of Mathematics, Changshu Institute of Technology, Changshu, China;2. Dipartimento di Matematica e Informatica U. Dini, Università di Firenze, Italy |
