منابع مشابه
Chordal Digraphs
Chordal graphs, also called triangulated graphs, are important in algorithmic graph theory. In this paper we generalise the definition of chordal graphs to the class of directed graphs. Several structural properties of chordal graphs that are crucial for algorithmic applications carry over to the directed setting, including notions like simplicial vertices, perfect elimination orderings, and ch...
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Competition graphs have appeared in a variety of applications from food webs to communication networks to energy models. The competition graph, C (D), of a digraph D has the same vertex set as D and (x; y) is an edge in C (D) if and only if there is a vertex z such that (x; z) and (y; z) are arcs in D. It has been observed that most actual food webs have interval competition graphs. Subsequent ...
متن کاملMore skew-equienergetic digraphs
Two digraphs of same order are said to be skew-equienergetic if their skew energies are equal. One of the open problems proposed by Li and Lian was to construct non-cospectral skew-equienergetic digraphs on n vertices. Recently this problem was solved by Ramane et al. In this paper, we give some new methods to construct new skew-equienergetic digraphs.
متن کاملChordal Graphs
One can prove the following propositions: (1) For every non zero natural number n holds n − 1 is a natural number and 1 ≤ n. (2) For every odd natural number n holds n − 1 is a natural number and 1 ≤ n. (3) For all odd integers n, m such that n < m holds n ≤ m − 2. (4) For all odd integers n, m such that m < n holds m + 2 ≤ n. (5) For every odd natural number n such that 1 6= n there exists an ...
متن کاملStrongly Chordal and Chordal Bipartite Graphs Are Sandwich Monotone
A graph class is sandwich monotone if, for every pair of its graphs G1 = (V,E1) and G2 = (V,E2) with E1 ⊂ E2, there is an ordering e1, . . . , ek of the edges in E2 \E1 such that G = (V,E1 ∪ {e1, . . . , ei}) belongs to the class for every i between 1 and k. In this paper we show that strongly chordal graphs and chordal bipartite graphs are sandwich monotone, answering an open question by Bakon...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2012
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2012.06.019