A better bound for locally thin set families

Authors
Fachini, E Korner, J Monti, A
Citation
E. Fachini et al., A better bound for locally thin set families, J COMB TH A, 95(2), 2001, pp. 209-218
Citations number
9
Categorie Soggetti
Mathematics
Journal title
JOURNAL OF COMBINATORIAL THEORY SERIES A
ISSN journal
00973165 → ACNP
Volume
95
Issue
2
Year of publication
2001
Pages
209 - 218
Database
ISI
SICI code
0097-3165(200108)95:2<209:ABBFLT>2.0.ZU;2-H
Abstract
A family of subsets of an n-set is 4-locally thin if for every quadruple of its members the ground set has at least one element contained in exactly I of them. We show that such a family has at most 2(0.4561n) members. This i mproves on our previous results with Noga Alon. The new proof is based on a more careful analysis of the self-similarity of the graph associated with such set families by the graph entropy bounding technique. (C) 2001 Academi c Press.