“…Under the non-essential distinctions elimination category, all of those [32], [33], [43], [59], [60], [82]- [85] reduction methods have formal context as a preliminary step for the reduction process, except for the method in [86], which has both formal context and formal concepts as a point to start the reduction process and the method in [76], which has both formal concepts and concept lattice as a preliminary step for the reduction process. In the concept filtration category, eight methods [65], [71], [79], [82], [87]- [90] use formal context as a preliminary step for the reduction process, four methods [35], [64], [91], [92] use concept lattice as a preliminary step for the reduction process, three reduction methods [61], [69], [73] use both formal concepts and concept lattice as a preliminary step for the reduction process, and two reduction methods [20], [36] use both formal context and formal concepts as a preliminary step for the reduction process. The approach can be enhanced by using domain experts (prior knowledge) about the domain problem to lead the reduction process.…”