Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"planar graph"”.
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Small cycle cover, group coloring with related problems
… conjectured that if G is a simple 2-connected graph with n ≥ 3 vertices, then the edges of G can be covered by at most 2n-33 cycles. In Chapter 2, a result on small cycle cover is obtained and we also show that the result is as best as possible.;Thomassen conjectured that every 4-connected …
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Acyclic 5-Choosability of Planar Graphs Without Adjacent Short Cycles
The conjecture claiming that every planar graph is acyclic 5-choosable[Borodin et al., 2002] has been verified for several restricted classes of planargraphs. Recently, O. V. Borodin and A. O. Ivanova, [Journal of Graph Theory,68(2), October 2011, 169-176], have shown that a planar graph is …
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Hamiltonian cycles in maximal planar graphs and planar triangulations
In this thesis we study planar graphs, in particular, maximal planar graphs and general planar triangulations. In Chapter 1 we present the terminology and notations that will be used throughout the thesis and review some elementary results on graphs that we shall need. In Chapter 2 we study the …
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Extremal Problems for Partitions of Edge Sets of Graphs
… thesis considers three families of problems in graph theory about partitions of the edge sets of graphs (also known as graph decompositions). The first family we address consists of induced Ramsey number problems. Induced Ramsey numbers generalize ordinary Ramsey numbers. The induced Ramsey …
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The Configuration Space of Two Particles Moving on a Graph
… of two particles moving without collisions on a graph Γ with a view to calculating the Betti numbers of this space. We develop an intersection theory for cycles in graphs inspired by the classical intersection theory for cycles in manifolds and we use this to develop an algorithm to calculate the …
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Accelerating dynamic programming
… We introduce this scheme in the context of planar graph problems. In particular, we show that planar graph problems such as shortest paths, feasible flow, bipartite perfect matching, and replacement paths can be accelerated by DPs that exploit a total-monotonicity property of the shortest …
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Edge-choosability of Planar Graphs
… to the List Colouring Conjecture, if G is a multigraph then χ' (G)=χl' (G) . In this thesis, we discuss a relaxed version of this conjecture that every simple graph G is edge-(∆ + 1)-choosable as by Vizing’s Theorem ∆(G) ≤χ' (G)≤∆(G) + 1. We prove that if G is a planar graph without 7-cycles with …
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Infinite Planar Graphs
… many equivalence classes of geodesic rays does a graph contain? How many bounded automorphisms does a planar graph have? Neimayer and Watkins studied these two questions and answered them for a certain class of graphs. Using the concept of excess of a vertex, the class of graphs that Neimayer and …
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Graph representations using stars, trees, intervals and boxes
We introduce star number (tree number) of a graph G, which is the minimum t such that G is the intersection graph of unions of t substars (subtrees) of a host tree. We characterize the graphs with star number 1 and prove that a planar graph has star number at most 3. We study bounds on these two …
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Product Structure, Separating Systems, Freeze-Tag Problem, and Planar Multicolor Turan Number
… is based on a collection of papers focused on graph theory and computational geometry. The first paper focuses on the Product Structure Theorem for planar graphs, which asserts that any planar graph can be embedded in the strong product of a planar 3-tree, a path, and a 3-cycle. The paper …
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Equilibrium graphs on the flat torus or finding zen amidst the bull
… spring embedding theorem, and equilibrium graphs on the plane in general, have been a subject of study for many decades, with connections to and applications in many areas, including, but not limited to, discrete geometry, planar graph theory, graphics, surface parametrization, mechanical …
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Coloring and covering problems on graphs
The \emph{separation dimension} of a graph $G$, written $\pi(G)$, is the minimum number of linear orderings of $V(G)$ such that every two nonincident edges are ``separated'' in some ordering, meaning that both endpoints of one edge appear before both endpoints of the other. We introduce the …
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Distances in planar graphs
In graph theory, the degree diameter problem asks for the maximum number of vertices a graph with given maximum degree and diameter can have. The face-degree of a face in plane graph is the length of the shortest closed walk traversing the boundary of the face. A plane graph is ρ-face-degree …
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On 4-Regular Planar Hamiltonian Graphs
… uniform probability as possible. The underlying graph of a knot diagram can be viewed as a 4-regular planar graph. The existence of a Hamiltonian cycle in such a graph is necessary in order to use the graph to compute an upper bound on rope length for a given knot. The algorithm to generate such …
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Loop Edge Estimation in 4-Regular Hamiltonian Graphs
… that cannot be untangled to produce a simple planar loop. A mathematical knot is essentially a conventional knot tied with rope where the ends of the rope have been glued together. One way to sample large knots is based on choosing a 4-regular Hamiltonian planar graph. A method for generating …
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A solution to the Papadimitriou-Ratajczak conjecture
Geographic Routing is a family of routing algorithms that uses geographic point locations as addresses for the purposes of routing. Such routing algorithms have proven to be both simple to implement and heuristically effective when applied to wireless sensor networks. Greedy Routing is a natural …
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Robust distribution sensor network localization with noisy range measurements
… the localization problem as a two-dimensional graph realization problem: given a planar graph with approximately known edge lengths, recover the Euclidean position of each vertex up to a global rotation and translation. This formulation is applicable to the localization of sensor networks in …
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A Sparsification Based Algorithm for Maximum-Cardinality Bipartite Matching in Planar Graphs
… is one of the most fundamental algorithmic graph problems. Many variants of matching problems have been studied on different classes of graphs, the one of special interest to us being the Maximum Cardinality Bipartite Matching in Planar Graphs. In this work, we present a novel sparsification …
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The Four Color Theorem: A Possible New Approach
… goal of this thesis is to explore the topic of graph coloring and expand on existing ideas in the field of Graph Theory. These developments will then be used to provide a possible approach in proving the 4 – color theorem that was made famous by Guthrie in the 1800’s.</p> <p>Since the theorem …
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Chords of longest circuits of graphs
… Thomassen: Every longest circuit of 3-connected graph has a chord. In 1987, C. Q. Zhang proved that every longest circuit of a 3-connected planar graph G has a chord if G is cubic or if the minimum degree is at least 4. In 1997, Carsten Thomassen proved that every longest circuit of 3-connected …
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