Kernels and partial line digraphs
نویسندگان
چکیده
منابع مشابه
Relation between number of kernels (and generalizations) of a digraph and its partial line digraphs
Let D = (V,A) be a digraph and consider an arc subset A ⊆ A and a surjective mapping φ : A → A such that, i) the set of heads of A is H(A) = V and ii) φ|A = Id and for every vertex j ∈ V , φ(ω(j)) ⊂ ω(j) ∩ A. Then, the partial line digraph of D, denoted by L(A′,φ)D (for short LD if the pair (A , φ) is clear from the context), is the digraph with vertex set V (LD) = A and set of arcs A(LD) = {(i...
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Let D be a digraph, V (D) and A(D) will denote the sets of vertices and arcs of D, respectively. A kernel N of D is an independent set of vertices such that for every w∈V (D) − N there exists an arc from w to N . A digraph D is called right-pretransitive (resp. left-pretransitive) when (u; v)∈A(D) and (v; w)∈A(D) implies (u; w)∈A(D) or (w; v)∈A(D) (resp. (u; v)∈A(D) and (v; w)∈A(D) implies (u; ...
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ژورنال
عنوان ژورنال: Applied Mathematics Letters
سال: 2010
ISSN: 0893-9659
DOI: 10.1016/j.aml.2010.06.001