## Zentralblatt MATH

Publications of (and about) Paul Erdös

Zbl.No:  217.30701
Autor:  Erdös, Paul; Herzog, M.; Schönheim, J.
Title:  An extremal problem on the set of noncoprime divisors of a number (In English)
Source:  Isr. J. Math. 8, 408-412 (1970).
Review:  A combinatorial theorem is established, stating that if a family A1,A2, ... ,As of subsets of a set M contains every subset of each member, then the complements in M of the A's have a permutation C1,C2, ... ,Cs such that Ci \supset A1. This is used to determine the minimal size of a maximal set of divisors of a number N no two of them being coprime.
Classif.:  * 05A05 Combinatorial choice problems

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