Uniquely colourable m-dichromatic oriented graphs

نویسندگان
چکیده

برای دانلود باید عضویت طلایی داشته باشید

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

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

A Note on Uniquely H-colourable Graphs

For a graph H, we compare two notions of uniquely H-colourable graphs, where one is defined via automorphisms, the second by vertex partitions. We prove that the two notions of uniquely H-colourable are not identical for all H, and we give a condition for when they are identical. The condition is related to the first homomorphism theorem from algebra.

متن کامل

Uniquely circular colourable and uniquely fractional colourable graphs of large girth

Given any rational numbers r ≥ r′ > 2 and an integer g, we prove that there is a graph G of girth at least g, which is uniquely circular r-colourable and uniquely fractional r′-colourable. Moreover, the graph G has maximum degree bounded by a number which depends on r and r′ but does not depend on g.

متن کامل

The existence of uniquely -G colourable graphs

Given graphs F and G and a nonnegative integer k, a function n : V(F) ~ {1 . . . . . k} is a G k-colouring of F if no induced copy of G is monochromatic; F is G k-chromatic if F has a G k-colouring but no G (k 1)-colouring. Further, we say F is uniquely G k-colourable if F is G k-chromatic and, up to a permutation of colours, it has only one G k-colouring. Such notions are extensions of the wel...

متن کامل

The property of kk-colourable graphs is uniquely decomposable

An additive hereditary graph property is a class of simple graphs which is closed under unions, subgraphs and isomorphisms. If P1, . . . ,Pn are graph properties, then a (P1, . . . ,Pn)-decomposition of a graph G is a partition E1, . . . , En of E(G) such that G[Ei], the subgraph of G induced by Ei, is in Pi, for i = 1, . . . , n. The sum of the properties P1, . . . ,Pn is the property P1 ⊕ · ·...

متن کامل

Uniquely D-colourable Digraphs with Large Girth

Let C and D be digraphs. A mapping f : V (D) → V (C) is a Ccolouring if for every arc uv of D, either f(u)f(v) is an arc of C or f(u) = f(v), and the preimage of every vertex of C induces an acyclic subdigraph in D. We say that D is C-colourable if it admits a C-colouring and that D is uniquely Ccolourable if it is surjectively C-colourable and any two C-colourings of D differ by an automorphis...

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

ژورنال

عنوان ژورنال: Discrete Mathematics

سال: 1986

ISSN: 0012-365X

DOI: 10.1016/0012-365x(86)90042-7