Interval-valued preference structures

Different languages that are offered to model vague preferences are reviewed and an interval-valued language is proposed to resolve a particular difficulty encountered with other languages. It is shown that interval-valued languages are well defined for De Morgan triples constructed by continuous triangular norms, conorms and a strong negation function. A new transitivity condition for vague preferences is suggested and its relationships to known transitivity conditions are established. A complete characterization of interval-valued preference structures is also provided.