کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4647577 | 1342359 | 2013 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The acyclic and Câ3-free disconnection of tournaments
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موضوعات مرتبط
مهندسی و علوم پایه
ریاضیات
ریاضیات گسسته و ترکیبات
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: The acyclic and Câ3-free disconnection of tournaments The acyclic and Câ3-free disconnection of tournaments](/preview/png/4647577.png)
چکیده انگلیسی
The acyclic disconnection Ïâ(D) of a digraph D is defined as the maximum number of colors in a coloring of the vertices of D such that no cycle is properly colored (in a proper coloring, consecutive vertices of the directed cycle receive different colors). Similarly, the Câ3-free disconnection Ïâ3(D) of D is the maximum number of colors in a coloring of the vertices of D such that no directed triangle is 3-colored. In this paper, we construct an infinite family Vn of tournaments T8n+1 with 8n+1 vertices (nâN) such that Ïâ3(T8n+1)=n+2 and Ïâ(T8n+1)=2. This family allows us to solve the following problem posed by V. Neumann-Lara [V. Neumann-Lara, The acyclic disconnection of a digraph, Discrete Math. 197/198 (1999) 617-632]: Are there tournaments T for which Ïâ(T)=2 and Ïâ3(T) is arbitrarily large? The main result of the paper solves a generalization of the above problem: for positive integers r and s such that 2â¤râ¤s, there exists a tournament T such that Ïâ(T)=r and Ïâ3(T)=s.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Discrete Mathematics - Volume 313, Issue 20, 28 October 2013, Pages 2348-2353
Journal: Discrete Mathematics - Volume 313, Issue 20, 28 October 2013, Pages 2348-2353
نویسندگان
José Luis Cosme-Álvarez, Bernardo Llano,