## Abstract This article proves the following result: Let __G__ and __G__โฒ be graphs of orders __n__ and __n__โฒ, respectively. Let __G__^\*^ be obtained from __G__ by adding to each vertex a set of __n__โฒ degree 1 neighbors. If __G__^\*^ has game coloring number __m__ and __G__โฒ has acyclic chromat
The Cartesian product of hypergraphs
โ Scribed by Lydia Ostermeier; Marc Hellmuth; Peter F. Stadler
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 236 KB
- Volume
- 70
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
โฆ Synopsis
Abstract
We show that every simple, (weakly) connected, possibly directed and infinite, hypergraph has a unique prime factor decomposition with respect to the (weak) Cartesian product, even if it has infinitely many factors. This generalizes previous results for graphs and undirected hypergraphs to directed and infinite hypergraphs. The proof adopts the strategy outlined by Imrich and ลฝerovnik for the case of graphs and introduces the notion of diagonalโfree grids as a replacement of the chordโfree 4โcycles that play a crucial role in the case of graphs. This leads to a generalization of relation ฮ on the arc set, whose convex hull is shown to coincide with the product relation of the prime factorization. ยฉ 2011 Wiley Periodicals, Inc. J Graph Theory
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## Abstract A set __S__ of vertices is a determining set for a graph __G__ if every automorphism of __G__ is uniquely determined by its action on __S__. The determining number of __G__, denoted Det(__G__), is the size of a smallest determining set. This paper begins by proving that if __G__=__G__โกโ
## Abstract The study of perfectness, via the strong perfect graph conjecture, has given rise to numerous investigations concerning the structure of many particular classes of perfect graphs. In โPerfect Product Graphsโ (__Discrete Mathematics__, Vol. 20, 1977, pp. 177โโ186), G. Ravindra and K. R.
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