Let G be a finite abelian group with exponent e, let r(G) be the minimal integer t with the property that any sequence of t elements in G contains an e-term subsequence with sum zero. In this paper we show that if r(C 2 n )=4n&3 and if n ((3m&4)(m&1) m 2 +3)Γ4m, then r(C 2 nm )=4nm&3. In particular,
On the number of zero sum subsequences
β Scribed by Weidong Gao
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 219 KB
- Volume
- 163
- Category
- Article
- ISSN
- 0012-365X
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β¦ Synopsis
Let Z. be the cyclic group of order n. For a sequence S of elements in Z~, we use f~(S) to denote the number of subsequences, the sum of whose elements is zero. In this paper, we give a characterization on the sequences S of elements in Zn for whichf~(S) < 2 Isl -" Γ· k -,, under the restriction 1 ~ k ~< Fn/4] + i. As consequences of this result, we obtain some further characterizations on the sequences S of n elements in Z. for which f.(S) is not large. Let Z. be the cyclic group of order n. For a sequence S = (at ..... ak) of elements in k Zn, we use ~ S to denote the sum ~ ~= t a~. By 2 we denote the empty sequence and adopt the convention that Y. 2 --0. We usef~(S) to denote the number of subsequences T of S with ~ T = 0. Clearly, f~(S) ~>f~(2) = 1. In ['3], to give a positive answer to a conjecture of Erd6s, Olson proved that if al ..... a, is a sequence of n nonzero elements in Zn, and if al ..... an are not all equal, thenfn(S) >I n. In this paper, we first give a characterization on the sequences S of elements in Zn with f~(S) < 2 Isl -" Γ· k-1 under the restriction 1 ~< k ~< ['n/4] + 1. As consequences of this result, we get some further characterizations on the sequences S of n elements in Z. for whichf.(S) is not large. Among these characterizations, we generalize both the result of Oson and a result of Bulman-Fleming and Wang.
π SIMILAR VOLUMES
Caro, Y., On zero-sum Ramsey numbers--stars, Discrete Mathematics 104 (1992) l-6. Let n 3 k 2 2 be positive integers, k ( n. Let H, be the cyclic group of order k. Denote by R(K,,,> Z,) the minimal integer t such that for every &-coloring of the edges of K,, (i.e., a function c : E(K,)+ hk), there i
## Abstract As a consequence of our main result, a theorem of Schrijver and Seymour that determines the zero sum Ramsey numbers for the family of all __r__βhypertrees on __m__ edges and a theorem of Bialostocki and Dierker that determines the zero sum Ramsey numbers for __r__βhypermatchings are com
## Abstract In this paper we introduce the notion of pseudo βergodicity to generalize Pustyl'nikov's estimates of Weyl sums to Weyl sums over subsequence of the natural numbers.
Let G be a bipartite graph, with k|e(G). The zero-sum bipartite Ramsey number B(G, Z k ) is the smallest integer t such that in every Z k -coloring of the edges of K t,t , there is a zero-sum mod k copy of G in K t,t . In this article we give the first proof that determines B(G, Z 2 ) for all possib