“…Researchers employed possibility theory. Much work was focused on extending Markowitz's mean-variance selection idea and a variety of fuzzy meanvariance models have been developed, e.g., Watada (1997), Tanaka and Guo (1999), Tanaka et al (2000), Arenas-Parra et al (2001), Carlsson et al (2002), Ida (2002), León et al (2002), Zhang and Nie (2004), Bilbao-Terol et al (2006), Lacagnina and Pecorella (2006), Zhang et al (2007) and Gupta et al (2008). In addition, Vercher et al (2007) presented a downside risk for fuzzy portfolio selection.…”