دانلود مقاله ISI انگلیسی شماره 79071
ترجمه فارسی عنوان مقاله

یک الگوریتم سریع تر برای بسته بندی در شاخه گراف جهت دا ر.

عنوان انگلیسی
A faster algorithm for packing branchings in digraphs
کد مقاله سال انتشار تعداد صفحات مقاله انگلیسی
79071 2015 11 صفحه PDF
منبع

Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)

Journal : Discrete Applied Mathematics, Volume 194, 30 October 2015, Pages 121–131

ترجمه کلمات کلیدی
نظریه گراف - شاخه بسته بندی ؛ بهینه سازی ترکیبی
کلمات کلیدی انگلیسی
Graph theory; Packing of branchings; Combinatorial optimization
پیش نمایش مقاله
پیش نمایش مقاله  یک الگوریتم سریع تر برای بسته بندی در شاخه گراف جهت دا ر.

چکیده انگلیسی

We consider the problem of finding an integral (and fractional) packing of branchings in a capacitated digraph with root-set demands. Schrijver described an algorithm that returns a packing with at most m+n3+rm+n3+r branchings that makes at most m(m+n3+r)m(m+n3+r) calls to an oracle that basically computes a minimum cut, where nn is the number of vertices, mm is the number of arcs and rr is the number of root-sets of the input digraph. Leston-Rey and Wakabayashi described an algorithm that returns a packing with at most m+r−1m+r−1 branchings but makes a large number of oracle calls. In this work we provide an algorithm, inspired on ideas of Schrijver and in a paper of Gabow and Manu, that returns a packing with at most m+r−1m+r−1 branchings and makes at most (m+r+2)n(m+r+2)n oracle calls. Moreover, for the arborescence packing problem our algorithm provides a packing with at most m−n+2m−n+2 arborescences–thus improving the bound of mm of Leston-Rey and Wakabayashi–and makes at most (m−n+5)n(m−n+5)n oracle calls.