Zero-sum problems -- a survey
The paper introduces basic concepts of the so-called zero-sum Ramsey theory and surveys major results in the area. In very informal terms, the problems of interest have the following general form: Suppose that the elements of a combinatorial structure are mapped into a finite group \(K\). Does there exist a substructure with the sum of the weights of its elements equal to 0 in \(K\)? The first result of this type is the celebrated Erdős-Ginzburg-Ziv theorem: Suppose \(m \geq k \geq 2\) are integers such that \(k|m\). Let \(a_1, \ldots, a_{m + k - 1}\) be a sequence of integers. Then there exists \(I \subseteq \{a_1, \dots, a_{m + k - 1}\}\) such that \(|I |= m\) and \(\sum_{i \in I} a_i \pmod k\). Another example of a zero-sum Ramsey problem appears in graph theory. The zero-sum Ramsey number \(R(H, Z_k)\) is the least integer \(t\) such that in any \(Z_k\)-coloring of the edges of the complete \(r\)-uniform hypergraph on \(t\) vertices there is a zero-sum copy of \(H\). The question is to determine \(R(H, Z_k)\). The survey discusses these two as well as many other related zero-sum problems. The survey is self-contained, comprehensive and includes an exhaustive list of references.
scientific article; zbMATH DE number 897570
scientific article