Document Type : Research Paper
Authors
^{1} Department of Mathematics, Mashhad Branch, Islamic Azad University, Mashhad, Iran.
^{2} Department of Mathematics, Khayyam University, Mashhad, Iran\ Department of Pure Mathematics, Centre of Excellence in Analysis on Algebraic Structures (CEAAS), Ferdowsi University of Mashhad, P.O.Box 1159, Mashhad, 91775, Iran.
^{3} Department of Mathematics, Khayyam University, Mashhad, Iran.
Abstract
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