Annals of Fuzzy Mathematics and Informatics Volume 12, No. 1, (July 2016), pp. 129–138 ISSN: 2093–9310 (print version) ISSN: 2287–6235 (electronic version) http://www.afmi.or.kr @FMI c  Kyung Moon Sa Co. http://www.kyungmoon.com Some results of mixed fuzzy soft topology and applications in Chemistry Manash Jyoti Borah, Bipan Hazarika Received 29 October 2015; Revised 7 January 2016; Accepted 1 February 2016 Abstract. In this paper, we introduce mixed fuzzy soft topology with separation axioms. Also we introduce soft quasi-coincident, soft quasi- neighborhood and obtain some related propositions. Finally, we provide an application of fuzzy soft sets in Chemistry. 2010 AMS Classification: 03E72 Keywords: Fuzzy soft sets, Soft quasi-coincident, Soft quasi-neighborhood. Corresponding Author: Bipan Hazarika (bh rgu@yahoo.co.in) 1. Introduction Fuzzy set theory proposed by Zadeh [22] in 1965 which is a generalization of classical or crisp sets. In 1999, Molodtsov [11] introduced the theory of soft sets, which is a new mathematical approach to vagueness. In 2003, Maji, Biswas and Roy [9] studied the theory of soft sets initiated by Molodtsov [11] and developed several basic notions of soft set theory. The notion of topological space is defined on crisp sets and hence it is affected by different generalizations of crisp sets like fuzzy sets and soft sets. In 1968, Chang [2] introduced fuzzy topological space and in 2011, subsequently C ¸ aˇ gmanandEnginoˇglu [1], Shabir and Naz [15] introduced fuzzy soft topological spaces and studied basic properties. In 2012, Mahanta and Das [8], Neog, Sut and Hazarika [12] and Ray and Samanta [13] introduced fuzzy soft topological spaces in different direction. For details on soft topological spaces we refer to [5, 6, 7, 10, 14, 19, 21]. The works on mixed topology is due to Wiweger [20], Cooper [3], Das and Baishya [4], Tripathy and Ray [17, 18] and many others. The technique of mixing topologies has a number of applications in various branches of analysis, notably summabil- ity theory, measure theory, locally compact spaces, and interpolation theorems for analytic functions.