Layered Concept Lattice Model and Its Application to Build Rapidly Concept Lattice
Algorithm 2
Drill-down algorithm to build the lower concept lattice.
Input: a concept lattice of formal context containing layered attributes.
Output: the lower concept lattice .
Step 1. For each lower attribute of a layered attribute ,:, build all attribute concepts: .
Step 2. The concept containing layered attribute is updated to some new concepts , which contain lower attributes ,, respectively, where is not an empty set. The concepts that do not contain the layered attribute remain the same.
Step 3. If some concepts with lower attributes obtained from Step 2 can be combined, then these concepts are combined and a concept and is inserted above them.
Step 4. The node concepts that are connected to and are also not updated in are connected to the updated node concepts.
Step 5. For each layered attribute , repeat from Step 1 to Step 4 above.
