{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,30]],"date-time":"2025-07-30T16:43:06Z","timestamp":1753893786873,"version":"3.41.2"},"reference-count":0,"publisher":"The Electronic Journal of Combinatorics","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Electron. J. Combin."],"abstract":"<jats:p>The Berger-Felzenbaum-Fraenkel approach to Covering Systems is exposited. In particular their gorgeous proof of the famous $a_n=a_{n-1}$ theorem for exact covering systems (found independently by Jamie Simpson), is reviewed, and the analogy of their approach to Boolean tautologies in Disjunctive Normal Form is pointed out.<\/jats:p>","DOI":"10.37236\/1617","type":"journal-article","created":{"date-parts":[[2020,1,11]],"date-time":"2020-01-11T02:24:26Z","timestamp":1578709466000},"source":"Crossref","is-referenced-by-count":2,"title":["How Berger, Felzenbaum and Fraenkel Revolutionized Covering Systems the Same Way that George Boole Revolutionized Logic"],"prefix":"10.37236","volume":"8","author":[{"given":"Doron","family":"Zeilberger","sequence":"first","affiliation":[]}],"member":"23455","published-online":{"date-parts":[[2000,4,7]]},"container-title":["The Electronic Journal of Combinatorics"],"original-title":[],"link":[{"URL":"https:\/\/www.combinatorics.org\/ojs\/index.php\/eljc\/article\/download\/v8i2a1\/pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.combinatorics.org\/ojs\/index.php\/eljc\/article\/download\/v8i2a1\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,1,18]],"date-time":"2020-01-18T05:24:36Z","timestamp":1579325076000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.combinatorics.org\/ojs\/index.php\/eljc\/article\/view\/v8i2a1"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000,4,7]]},"references-count":0,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2001,2,6]]}},"URL":"https:\/\/doi.org\/10.37236\/1617","relation":{},"ISSN":["1077-8926"],"issn-type":[{"type":"electronic","value":"1077-8926"}],"subject":[],"published":{"date-parts":[[2000,4,7]]},"article-number":"A1"}}