{"id":"https://openalex.org/keywords/lower-approximation","display_name":"lower approximation","description":"In rough set theory, a lower approximation is the set of elements whose equivalence classes are wholly contained within a target set.","display_name_alternatives":["lower approximations","rough set lower approximation","lower rough approximation"],"ids":{"openalex":"https://openalex.org/keywords/lower-approximation","wikidata":null},"primary_topic":{"id":"https://openalex.org/T11063","display_name":"Rough Sets and Fuzzy Logic","score":0.8077,"subfield":{"id":"https://openalex.org/subfields/1703","display_name":"Computational Theory and Mathematics"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T11063","display_name":"Rough Sets and Fuzzy Logic","score":0.8077,"subfield":{"id":"https://openalex.org/subfields/1703","display_name":"Computational Theory and Mathematics"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"works_count":511,"cited_by_count":9044,"works_api_url":"https://api.openalex.org/works?filter=keywords.id:keywords/lower-approximation","updated_date":"2026-10-19T04:06:21","created_date":"2022-04-12T19:38:12"}