216 research outputs found
Some Results on Zero Sum Sequences in
Kemnitz Conjecture [9] states that if we take a sequence of elements in
of length , is a prime number, then it has a subsequence
of length , whose sum is modulo . It is known that in to
get a similar result we have to take a sequence of length atleast . In
this paper we will show that if we add a condition on the chosen sequence, then
we can get a good upper and a lower bound for which similar results hold.Comment: This was a part of my master thesis under Prof. Gautami Bhowmi
Zero-sum problems for abelian p-groups and covers of the integers by residue classes
Zero-sum problems for abelian groups and covers of the integers by residue
classes, are two different active topics initiated by P. Erdos more than 40
years ago and investigated by many researchers separately since then. In an
earlier announcement [Electron. Res. Announc. Amer. Math. Soc. 9(2003), 51-60],
the author claimed some surprising connections among these seemingly unrelated
fascinating areas. In this paper we establish further connections between
zero-sum problems for abelian p-groups and covers of the integers. For example,
we extend the famous Erdos-Ginzburg-Ziv theorem in the following way: If
{a_s(mod n_s)}_{s=1}^k covers each integer either exactly 2q-1 times or exactly
2q times where q is a prime power, then for any c_1,...,c_k in Z/qZ there
exists a subset I of {1,...,k} such that sum_{s in I}1/n_s=q and sum_{s in
I}c_s=0. Our main theorem in this paper unifies many results in the two realms
and also implies an extension of the Alon-Friedland-Kalai result on regular
subgraphs
Kemnitz’ conjecture revisited
AbstractA conjecture of Kemnitz remained open for some 20 years: each sequence of 4n-3 lattice points in the plane has a subsequence of length n whose centroid is a lattice point. It was solved independently by Reiher and di Fiore in the autumn of 2003. A refined and more general version of Kemnitz’ conjecture is proved in this note. The main result is about sequences of lengths between 3p-2 and 4p-3 in the additive group of integer pairs modulo p, for the essential case of an odd prime p. We derive structural information related to their zero sums, implying a variant of the original conjecture for each of the lengths mentioned. The approach is combinatorial
Zero-sum problems with congruence conditions
For a finite abelian group and a positive integer , let denote the smallest integer such that
every sequence over of length has a nonempty zero-sum
subsequence of length . We determine for all when has rank at most two and, under mild
conditions on , also obtain precise values in the case of -groups. In the
same spirit, we obtain new upper bounds for the Erd{\H o}s--Ginzburg--Ziv
constant provided that, for the -subgroups of , the Davenport
constant is bounded above by . This
generalizes former results for groups of rank two
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