J. Math. Computer Sci., 31 (2023), 240–246 Online: ISSN 2008-949X Journal Homepage: www.isr-publications.com/jmcs Strongly separation axioms in fuzzifying bitopological spaces H. M. Binshahnah a , A. K. Mousa b,c,* , A. A. Allam d a Department of Mathematics, Faculty of Science, Hadhramout University, Yemen. b Department of Mathematics, Faculty of Science, Al-Azhar University, Assiut 71524, Egypt. c Department of Mathematics, College of Umluj, University of Tabuk, K.S.A. d Department of Mathematics, Faculty of Science, Assiut University, Assiut 71516, Egypt. Abstract In this paper, we study the pairwise open sets in the fuzzifying bitopological spaces and obtain new results. Also, we investigate of separation axioms in the fuzzifying bitopological spaces and obtain important results. Furthermore, we introduce and study new strongly pairwise axioms in the fuzzifying bitopological spaces. Keywords: Fuzzifying topology, fuzzifying bitopological space, separation axioms. 2020 MSC: 54E55, 54D15, 54D10. ©2023 All rights reserved. 1. Introduction The study of bitopological spaces was first initiated by Kelley [4] in 1963. In 1991-1993 [7–9], Ying studied the basic concepts of the fuzzifying topological spaces (briefly, FTSs) using the fuzzy logic. In 1993 Shen [6] introduced and studied the separation axioms in the FTSs. In 2003 Zhang et al. [10], defined the fuzzifying bitopological spaces (briefly, FBTSs) and studied more concepts in this subject. In 2007 Kilicman et al. [5], continued the study of bitopological separation axioms which introduced by Kelley. In 2020, Allam et al. [1], introduced and investigated the separation axioms in the FBTSs. In 2019-2020 Al-Shami et al [2, 3], studied and investigated different types of separation axioms in soft topology (consider as an extension of fuzzy topology). This paper is presented as follows. In Section 3, the pairwise open sets in the FBTSs were studied and some of new results between pairwise closure and pairwise interior operators were obtained. In Section 4, some important results regarding a pairwise normality, a weakly pairwise normality and a pairwise regularity in the FBTSs were obtained. In Section 5, the concept of a new strongly pairwise axioms in the FBTSs was introduced and studied. Finally, in Section 6 a conclusion is given. * Corresponding author Email address: akmousa@azhar.edu.eg (A. K. Mousa) doi: 10.22436/jmcs.031.03.01 Received: 2021-08-21 Revised: 2023-01-16 Accepted: 2023-01-30