“…They also showed that this expectation remains additive in the sense of addition of fuzzy numbers. Treating each return rate as a fuzzy number restricted by a possibility distribution, various possibilistic portfolio selection problems are discussed by Inuiguchi and Tanino (2000), Tanaka et al (2000), Guo et al (2002), Tanaka and Guo (1999), Carisson and Fullër (2001), Zhang and Nie (2003), Zhang and Wang (2005), Zhang (2007), Zhang et al (2007), Carlsson et al (2002), Vasant (2006), Bhattacharya and Vasant (2007), Inuiguchi et al (1992Inuiguchi et al ( , 1993. Tanaka and Guo (1999) proposed two kinds of portfolio selection models based on upper and lower exponential possibility distributions.…”