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 to
A characterisation of universal minimal total dominating functions in trees
โ Scribed by E.J. Cockayne; C.M. Mynhardt
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 445 KB
- Volume
- 141
- Category
- Article
- ISSN
- 0012-365X
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โฆ Synopsis
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 MTDF whose convex combinations with any other MTDF are minimal is called a universal MTDF. In this paper we characterise universal MTDFs for trees.
๐ SIMILAR VOLUMES
## Abstract A total dominating function (TDF) of a graph __G__ = (__V, E__) is a function __f__: __V__ โ [0, 1] such that for each __v__ ฯต V, ฮฃ~uฯตN(v)~ f(u) โฅ 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 โ [0, 1] such that for each v โ 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