A fuzzy description on some ecological concept

From the view of fuzzy set theory, first, we discuss competition of species i and j for many type resources (basic resource, less important resource, occasional resource and replaceable resource). The membership functions of all resources were given by using fuzzy tone operator, the fuzzy competition coefficient of two species was also supplied here; second, by using fuzzy set theory, fuzzy niche was given. Based on that, fuzzy measurement of niche width and overlap were also discussed here. All these are helpful for study the competition and coexist of the species.