A t-wise balanced design (tBD) of type t-vY KY ! is a pair XY Bwhere X is a velement set of points and B is a collection of subsets of X called blocks with the property that the size of every block is in K and every t-element subset of X is contained in exactly ! blocks. If K is a set of positive in
A hole-size bound for incomplete t-wise balanced designs
β Scribed by Donald L. Kreher; Rolf S. Rees
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 140 KB
- Volume
- 9
- Category
- Article
- ISSN
- 1063-8539
- DOI
- 10.1002/jcd.1011
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β¦ Synopsis
Abstract
An incomplete tβwise balanced design of index Ξ» is a triple (X,H,β¬οΈ) where X is a Ο βelement set, H is a subset of X called the hole, and B is a collection of subsets of X called blocks, such that, every tβelement subset of X is either in H or in exactly Ξ» blocks, but not both. If H is a hole in an incomplete tβwise balanced design of order Ο and index Ξ», then |H| β€ Ο /2 if t is odd and |H|ββ€β(Ο βββ1)/2 if t is even. In particular, this result establishes the validity of Kramer's conjecture that the maximal size of a block in a Steiner tβwise balanced design is at most Ο /2 if t is odd and at most (Ο β1)/2 when t is even. Β© 2001 John Wiley & Sons, Inc. J Combin Designs 9: 269β284, 2001
π SIMILAR VOLUMES
## Abstract Kreher and Rees 3 proved that if __h__ is the size of a hole in an incomplete balanced design of order Ο and index Ξ» having minimum block size $k \ge t+1$, then, They showed that when __t__β=β2 or 3, this bound is sharp infinitely often in that for each __h__ββ₯β__t__ and each __k__ββ₯β_