Bar-Ilan Combinatorics Seminar
 
The first meeting of the seminar in Semester B will take place, IYH,
 
(when)  Sunday, 10 Adar (March 4), 14:00-15:30
 
(where) Room 201 (Math & CS Seminar Room), Building 216, Bar-Ilan
University
 
(who)   Zur Luria (Hebrew University)
 
(what)  Upper bounds on the number of Steiner triple systems and
1-factorizations
 
Abstract:
 
A 1-factorization of the complete graph Kn is a partition of its
edges into n-1 perfect matchings. A Steiner triple system on [n] =
{1,...,n} is a collection T of triples such that each pair in [n] is
contained in a unique triple.
 
We will discuss the connections between these (and other) objects,
and present previously known bounds on their number. We'll prove that
the number of 1-factorizations of Kn is at most ((1+o(1))
n/e^2)^(n^2/2) and that the number of Steiner triple systems on [n]
is at most ((1+o(1)) n/e^2)^(n^2/6).
 
The proofs make use of information entropy.
 
Joint work with Nati Linial.
 
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You are all invited! Graduate students are especially welcome.
Seminar organizer: Ron Adin   <radin@math.biu.ac.il> 
Seminar's homepage:
  <http://www.math.biu.ac.il/~radin/comsem/comsem.html> 
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---------------------------------------------------------
Technion Math Net-2 (TECHMATH2)
Editor: Michael Cwikel   <techm@math.technion.ac.il> 
Announcement from: Ron Adin   <radin@math.biu.ac.il>