Revealed Preference, Congruence and Rationality: A Fuzzy Approach

In a previous paper connections between the congruence axioms WFCA, SFCA and the revealed preference axioms WAFRP, SAFRP for fuzzy choice functions whose domain contains the characteristic functions of pairs and of triples of alternatives have been studied. The first objective of this paper is to establish such connections for the case of arbitrary fuzzy choice functions. We introduce the new revealed preference axioms WAFRP°, SAFRP°, HAFRP and we prove two main theorems: 1. The axioms WFCA and WAFRP° are equivalent; 2. The axioms SFCA and HAFRP are equivalent. Our second objective is to define G-rational, M-rational, G-normal and M-normal fuzzy choice functions and to investigate some of their properties. The notions and the results are formulated in terms of the residuum of the Gödel t-norm and the proofs use the residuated lattice structure of the interval [0, 1].