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Related papers: Multicommodity Flows in Planar Graphs with Demands…

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An octilinear drawing of a planar graph is one in which each edge is drawn as a sequence of horizontal, vertical and diagonal at 45 degrees line-segments. For such drawings to be readable, special care is needed in order to keep the number…

Computational Geometry · Computer Science 2015-12-16 Michael A. Bekos , Michael Kaufmann , Robert Krug

Considering regions in a map to be adjacent when they have nonempty intersection (as opposed to the traditional view requiring intersection in a linear segment) leads to the concept of a facially complete graph: a plane graph that becomes…

Combinatorics · Mathematics 2024-09-18 James Tilley , Stan Wagon , Eric Weisstein

We give an $O(n^{1.5} \log n)$ algorithm that, given a directed planar graph with arc capacities, a set of source nodes and a single sink node, finds a maximum flow from the sources to the sink . This is the first subquadratic-time strongly…

Data Structures and Algorithms · Computer Science 2010-09-15 Philip N. Klein , Shay Mozes

The multicommodity flow problem is a classic problem in network flow and combinatorial optimization, with applications in transportation, communication, logistics, and supply chain management, etc. Existing algorithms often focus on…

Data Structures and Algorithms · Computer Science 2023-04-25 Li Chen , Mingquan Ye

We develop a new technique for computing maximum flow in directed planar graphs with multiple sources and a single sink that significantly deviates from previously known techniques for flow problems. This gives rise to an…

Discrete Mathematics · Computer Science 2011-05-11 Philip N. Klein , Shay Mozes

In this paper, we study curve shortening flows on rotational surfaces in $\mathbb{R}^3$. We assume that the surfaces have negative Gauss curvatures and that some condition related to the Gauss curvature and the curvature of embedded curve…

Differential Geometry · Mathematics 2022-03-02 Naotoshi Fujihara

In this paper, we present a constructive and proof-relevant development of graph theory, including the notion of maps, their faces, and maps of graphs embedded in the sphere, in homotopy type theory. This allows us to provide an elementary…

Logic in Computer Science · Computer Science 2024-11-20 Jonathan Prieto-Cubides , Håkon Robbestad Gylterud

Path cover is a well-known intractable problem that finds a minimum number of vertex disjoint paths in a given graph to cover all the vertices. We show that a variant, where the objective function is not the number of paths but the number…

Data Structures and Algorithms · Computer Science 2018-03-09 Yinhui Cai , Guangting Chen , Yong Chen , Randy Goebel , Guohui Lin , Longcheng Liu , An Zhang

We investigate the problem of constructing planar drawings with few bends for two related problems, the partially embedded graph problem---to extend a straight-line planar drawing of a subgraph to a planar drawing of the whole graph---and…

Computational Geometry · Computer Science 2014-10-31 Timothy M. Chan , Fabrizio Frati , Carsten Gutwenger , Anna Lubiw , Petra Mutzel , Marcus Schaefer

Motivated by finding planar embeddings that lead to drawings with favorable aesthetics, we study the problems MINMAXFACE and UNIFORMFACES of embedding a given biconnected multi-graph such that the largest face is as small as possible and…

Computational Geometry · Computer Science 2014-09-17 Giordano Da Lozzo , Vít Jelínek , Jan Kratochvíl , Ignaz Rutter

Maximum flow (and minimum cut) algorithms have had a strong impact on computer vision. In particular, graph cuts algorithms provide a mechanism for the discrete optimization of an energy functional which has been used in a variety of…

Computer Vision and Pattern Recognition · Computer Science 2011-12-30 Camille Couprie , Leo Grady , Hugues Talbot , Laurent Najman

Designing and optimizing different flows in networks is a relevant problem in many contexts. While a number of methods have been proposed in the physics and optimal transport literature for the one-commodity case, we lack similar results…

Physics and Society · Physics 2021-10-13 Alessandro Lonardi , Enrico Facca , Mario Putti , Caterina De Bacco

This paper studies a variant of the minimum-cost flow problem in a graph with convex cost function where the demands at the vertices are functions depending on a one-dimensional parameter $\lambda$. We devise two algorithmic approaches for…

Data Structures and Algorithms · Computer Science 2022-03-25 Per Joachims , Max Klimm , Philipp Warode

Let $G=(V,E)$ be an undirected unweighted planar graph. Consider a vector storing the distances from an arbitrary vertex $v$ to all vertices $S = \{ s_1 , s_2 , \ldots , s_k \}$ of a single face in their cyclic order. The pattern of $v$ is…

Data Structures and Algorithms · Computer Science 2022-02-11 Shay Mozes , Nathan Wallheimer , Oren Weimann

Adapting Lindstr\"om's well-known construction, we consider a wide class of functions which are generated by flows in a planar acyclic directed graph whose vertices (or edges) take weights in an arbitrary commutative semiring. We give a…

Combinatorics · Mathematics 2012-01-31 Vladimir I. Danilov , Alexander V. Karzanov , Gleb A. Koshevoy

We consider the problem of finding a feasible single-commodity flow in a strongly connected network with fixed supplies and demands, provided that the sum of supplies equals the sum of demands and the minimum arc capacity is at least this…

Data Structures and Algorithms · Computer Science 2007-12-03 Bernhard Haeupler , Robert E. Tarjan

An improved fully polynomial-time approximation scheme and a greedy heuristic for the fractional length-bounded maximum multicommodity flow problem with unit edge-lengths are proposed. Computational experiments are carried out on benchmark…

Data Structures and Algorithms · Computer Science 2017-08-03 Pavel Borisovsky , Anton Eremeev , Sergei Hrushev , Vadim Teplyakov , Mikhail Vorozhtsov

There are many applications of max flow with capacities that depend on one or more parameters. Many of these applications fall into the "Source-Sink Monotone" framework, a special case of Topkis's monotonic optimization framework, which…

Discrete Mathematics · Computer Science 2022-01-07 Maxwell Allman , Venus Lo , S. Thomas McCormick

We study the problem of convexifying drawings of planar graphs. Given any planar straight-line drawing of an internally 3-connected graph, we show how to morph the drawing to one with strictly convex faces while maintaining planarity at all…

Computational Geometry · Computer Science 2019-01-29 Linda Kleist , Boris Klemz , Anna Lubiw , Lena Schlipf , Frank Staals , Darren Strash

Given $k$ pairs of terminals $\{(s_{1}, t_{1}), \ldots, (s_{k}, t_{k})\}$ in a graph $G$, the min-sum $k$ vertex-disjoint paths problem is to find a collection $\{Q_{1}, Q_{2}, \ldots, Q_{k}\}$ of vertex-disjoint paths with minimum total…

Data Structures and Algorithms · Computer Science 2015-07-23 Glencora Borradaile , Amir Nayyeri , Farzad Zafarani