A total dominating function (TDF) of a graph G = (V, E) is a function f: V~ [0, 1] such that for each v~ V, ~u~Ntv)f(u)>~ 1, where N(v) denotes the set of neighbours of v. Although convex combinations of TDFs are also TDFs, convex combinations of minimal TDFs (MTDFs) are not necessarily minimal. An
Universal minimal total dominating functions of trees
β Scribed by Alan Stacey
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 179 KB
- Volume
- 140
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
We show that any tree that has a universal minimal total dominating function has one which only takes 0-1 values. K 3 demonstrates that this fails for graphs in general.
Given a graph G =(V, E), for each vertex ve V let F(v) be the set of its neighbours (in particular, not including v itself). A total dominating function of G is a function f: V~[0, 1] such that for each v~ V, fly] := ~ f(u)>~l. u~F (v)
π SIMILAR VOLUMES
The relation Ye on the set of minimal dominating functions (MDFs) of a finite graph G is defined by f&?g if and only if any convex combination off and g is also an MDF. If fis a nonintegral MDF of a tree, the existence of another MDF with fewer nonintegral values and other desirable properties is es
## Abstract A total dominating function (TDF) of a graph __G__ = (__V, E__) is a function __f__: __V__ β [0, 1] such that for each __v__ Ο΅ V, Ξ£~uΟ΅N(v)~ f(u) β₯ 1 (where __N__(__v__) denotes the set of neighbors of vertex __v__). Convex combinations of TDFs are also TDFs. However, convex combinations
A total dominating function (TDF) of a graph G = (V, E) is a function f : V β [0, 1] such that for each v β V , the sum of f values over the open neighbourhood of v is at least one. Zero-one valued TDFs are precisely the characteristic functions of total dominating sets of G. We study the convexity