Colouring Polytopic Partitions in �

نویسنده

  • Michal Křížek
چکیده

We consider face-to-face partitions of bounded polytopes into convex polytopes in d for arbitrary d 1 and examine their colourability. In particular, we prove that the chromatic number of any simplicial partition does not exceed d+1. Partitions of polyhedra in 3 into pentahedra and hexahedra are 5and 6-colourable, respectively. We show that the above numbers are attainable, i.e., in general, they cannot be reduced.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Partitioning Based Algorithms for Some Colouring Problems

We discuss four variants of the graph colouring problem, and present algorithms for solving them. The problems are k-Colourability, Max Ind k-COL, Max Val k-COL, and, finally, Max k-COL, which is the unweighted case of the Max k-Cut problem. The algorithms are based on the idea of partitioning the domain of the problems into disjoint subsets, and then considering all possible instances were the...

متن کامل

Out-colourings of Digraphs

We study vertex colourings of digraphs so that no out-neighbourhood is monochromatic and call such a colouring an out-colouring. The problem of deciding whether a given digraph has an out-colouring with only two colours (called a 2-out-colouring) is NP-complete. We show that for every choice of positive integers r, k there exists a k-strong bipartite tournament which needs at least r colours in...

متن کامل

Acyclic, Star and Oriented Colourings of Graph Subdivisions

Let G be a graph with chromatic number χ(G). A vertex colouring of G is acyclic if each bichromatic subgraph is a forest. A star colouring of G is an acyclic colouring in which each bichromatic subgraph is a star forest. Let χa(G) and χs(G) denote the acyclic and star chromatic numbers of G. This paper investigates acyclic and star colourings of subdivisions. Let G′ be the graph obtained from G...

متن کامل

Cotranslational folding of membrane proteins probed by arrest-peptide-mediated force measurements.

Polytopic membrane proteins are inserted cotranslationally into target membranes by ribosome-translocon complexes. It is, however, unclear when during the insertion process specific interactions between the transmembrane helices start to form. Here, we use a recently developed in vivo technique to measure pulling forces acting on transmembrane helices during their cotranslational insertion into...

متن کامل

The Potts Model and Chromatic Functions of Graphs

Abstract. The U -polynomial of Noble and Welsh is known to have intimate connections with the Potts model as well as with several important graph polynomials. For each graph G, U(G) is equivalent to Stanley’s symmetric bad colouring polynomial XB(G). Moreover Sarmiento established the equivalence between U and the polychromate of Brylawski. Loebl defined the q-dichromate Bq(G, x, y) as a functi...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2002