Partial covering arrays and a generalized Erdos-Ko-Rado property
Abstract
The classical Erd\H os-Ko-Rado theorem states that if $k\le\floor{n/2}$ then the largest family of pairwise intersecting $k$-subsets of $[n]=\{0,1,...,n\}$ is of size ${{n-1}\choose{k-1}}$. A family of $k$ subsets satisfying this pairwise intersecting property is called an EKR family. We generalize the EKR property and provide asymptotic lower bounds on the size of the largest family ${\cal A}$ of $k$-subsets of $[n]$ that satisfies the following property: For each $A,B,C\in{\cal A}$, each of the four sets $A\cap B\cap C;A\cap B\cap C^C; A\cap B^C\cap C; A^C\cap B\cap C$ are non-empty. This generalized EKR (GEKR) property is motivated, generalizations are suggested, and a comparison is made with fixed weight 3-covering arrays. Our techniques are probabilistic.
- Publication:
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arXiv Mathematics e-prints
- Pub Date:
- December 2005
- DOI:
- arXiv:
- arXiv:math/0512139
- Bibcode:
- 2005math.....12139C
- Keywords:
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- Mathematics - Combinatorics;
- 05Bxx
- E-Print:
- 16 pages, 4 figures, 2 tables