How Berger, Felzenbaum and Fraenkel Revolutionized Covering Systems the Same Way that George Boole Revolutionized Logic
Doron Zeilberger · The Electronic Journal of Combinatorics · 2000
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.