منابع مشابه
Integrality of minimal unit circular-arc models
A proper circular-arc (PCA) model is a pairM = (C,A) where C is a circle and A is a family of inclusion-free arcs on C in which no two arcs of A cover C. A PCA model U is a (c, `, d, ds)-CA model when C has circumference c, all the arcs in A have length `, all the extremes of the arcs in A are at a distance at least d, and all the beginning points of the arcs in A are at a distance at least d+ ...
متن کاملThe net closes on trypanosomatids.
At the turn of the last century, Africa faced an epidemic of sleeping sickness. For a while in the 70’s, with the advent and targeted use of insecticides like DDT, it seemed the disease would be eradicated. Today, Africa faces another sleeping sickness epidemic, which it seems little better equipped to respond to than it was a century ago and sleeping sickness looks to be a disease which may be...
متن کاملCertifying Algorithms for Recognizing Proper Circular-Arc Graphs and Unit Circular-Arc Graphs
We give two new algorithms for recognizing proper circulararc graphs and unit circular-arc graphs. The algorithms either provide a model for the input graph, or a certificate that proves that such a model does not exist and can be authenticated in O(n) time.
متن کاملUnit Circular-Arc Graph Representations and Feasible Circulations
In a recent paper, Durán, Gravano, McConnell, Spinrad and Tucker described an algorithm of complexity O(n2) for recognizing whether a graph G with n vertices and m edges is a unit circular-arc (UCA) graph. Furthermore the following open questions were posed in the above paper: (i) Is it possible to construct a UCA model for G in polynomial time?; (ii) Is it possible to construct a UCA model, wh...
متن کاملExtending Partial Representations of Unit Circular-arc Graphs
The partial representation extension problem, introduced by Klav́ık et al. (2011), generalizes the recognition problem. In this short note we show that this problem is NP-complete for unit circular-arc graphs.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nature
سال: 1978
ISSN: 0028-0836,1476-4687
DOI: 10.1038/273102b0