Incremental double sequence algorithm of concept lattice union

In existing literatures,the algorithms of concept lattice union are all one-way vertical or horizontal union.Based on concept lattice duality principle,this paper proposed a two-way union algorithm.Comparing with vertical or horizontal algorithms,this algorithm does union by the ascending and descending order of the intension and extension of concept.Algorithm analysis and example show that the new algorithm retains the structural information and its efficiency is significantly improved.