Variable threshold concept lattices

In this paper, the definition of a variable threshold concept lattice is introduced. Based on a Galois connection, three kinds of variable threshold concept lattices, in which diverse requirements of knowledge discovery can be satisfied by adjusting a threshold, are defined. The number of formal concepts in a variable threshold concept lattice is far less than that in a fuzzy concept lattice. The three kinds of variable threshold concept lattices are constructed between two crisp sets, between a crisp set and a fuzzy set, and between a fuzzy set and a crisp set. Their properties are analogous to that of the classical concept lattices, and can be induced by the fuzzy concept lattice.