scholarly journals A Polynomial Time Solution to Minimum Forwarding Set Problem in Wireless Networks under Unit Disk Coverage Model

2009 ◽  
Vol 20 (7) ◽  
pp. 913-924 ◽  
Author(s):  
M. Baysan ◽  
K. Sarac ◽  
R. Chandrasekaran ◽  
S. Bereg
2012 ◽  
Vol 21 (05) ◽  
pp. 1250043 ◽  
Author(s):  
MATTHIEU CALVEZ ◽  
BERT WIEST

We give an algorithm which decides the Nielsen–Thurston type of a given four-strand braid. The complexity of our algorithm is quadratic with respect to word length. The proof of its validity is based on a result which states that for a reducible 4-braid which is as short as possible within its conjugacy class (short in the sense of Garside), reducing curves surrounding three punctures must be round or almost round. As an application, we give a polynomial time solution to the conjugacy problem for non-pseudo-Anosov four-strand braids.


1998 ◽  
Vol 65 (4) ◽  
pp. 201-207 ◽  
Author(s):  
Chung Keung Poon ◽  
Zhu Binhai ◽  
Chin Francis

2021 ◽  
Author(s):  
Yasaman KalantarMotamedi

P vs NP is one of the open and most important mathematics/computer science questions that has not been answered since it was raised in 1971 despite its importance and a quest for a solution since 2000. P vs NP is a class of problems that no polynomial time algorithm exists for any. If any of the problems in the class gets solved in polynomial time, all can be solved as the problems are translatable to each other. One of the famous problems of this kind is Hamiltonian cycle. Here we propose a polynomial time algorithm with rigorous proof that it always finds a solution if there exists one. It is expected that this solution would address all problems in the class and have a major impact in diverse fields including computer science, engineering, biology, and cryptography.


2018 ◽  
Vol 28 (04) ◽  
pp. 341-363
Author(s):  
Rom Aschner ◽  
Paz Carmi ◽  
Yael Stein

We study unique coverage problems with rectangle and half-strip regions, motivated by wireless networks in the context of coverage using directional antennae without interference. Given a set [Formula: see text] of points (clients) and a set [Formula: see text] of directional antennae in the plane, the goal is to assign a direction to each directional antenna in [Formula: see text], such that the number of clients in [Formula: see text] that are uniquely covered by the directional antennae is maximized. A client is covered uniquely if it is covered by exactly one antenna. We consider two types of rectangular regions representing half-strip directional antennae: unbounded half-strips and half-strips bounded by a range [Formula: see text] (i.e., [Formula: see text]-sided rectangular regions and rectangular regions). The directional antennae can be directed up or down. We present two polynomial time algorithms: an optimal solution for the problem with the [Formula: see text]-sided rectangular regions, and a constant factor approximation for the rectangular regions.


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