Fuzzy extension of a classical function: An alternative to the knowledge base for modelling imprecise relations

A fuzzy extension f‾ defined in this way is a useful alternative to the set of fuzzy rules or knowledge base for modelling inherently imprecise relations, which are frequently described in a simplified manner by means of classical functions. For this reason, fuzzy extensions can be applied to a number of different fields, being particularly suitable for environmental assessments, such as the design and evaluation of environmental quality indexes and the environmental impact assessments, among others.