Title
Computer-aided proof of Erdos discrepancy properties
Abstract
In 1930s Paul Erd¿s conjectured that for any positive integer C in any infinite ¿1 sequence ( x n ) there exists a subsequence x d , x 2 d , x 3 d , ¿ , x k d , for some positive integers k and d, such that | ¿ i = 1 k x i ¿ d | C . The conjecture has been referred to as one of the major open problems in combinatorial number theory and discrepancy theory. For the particular case of C = 1 a human proof of the conjecture exists; for C = 2 a bespoke computer program had generated sequences of length 1124 of discrepancy 2, but the status of the conjecture remained open even for such a small bound. We show that by encoding the problem into Boolean satisfiability and applying the state of the art SAT solvers, one can obtain a discrepancy 2 sequence of length 1160 and a proof of the Erd¿s discrepancy conjecture for C = 2 , claiming that no discrepancy 2 sequence of length 1161, or more, exists. In the similar way, we obtain a precise bound of 127¿645 on the maximal lengths of both multiplicative and completely multiplicative sequences of discrepancy 3. We also demonstrate that unrestricted discrepancy 3 sequences can be longer than 130¿000.
Year
DOI
Venue
2014
10.1016/j.artint.2015.03.004
Artif. Intell.
Keywords
DocType
Volume
computer-aided proof,erdos discrepancy problem,propositional satisfiability
Journal
224
Issue
ISSN
Citations 
C
0004-3702
10
PageRank 
References 
Authors
0.57
18
2
Name
Order
Citations
PageRank
Boris Konev156942.08
Alexei Lisitsa227245.94