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 123 for “"subgraphs"”.
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Extremal problems involving forbidden subgraphs
… we study extremal problems involving forbidden subgraphs. We are interested in extremal problems over a family of graphs or over a family of hypergraphs. In Chapter 2, we consider improper coloring of graphs without short cycles. We find how sparse an improperly critical graph can be when it has …
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Edge-packing by isomorphic subgraphs
Maximum G Edge-Packing (E Pack<sub>G</sub>) is the problem of finding the maximum number of edge-disjoint isomorphic copies of a fixed guest graph G in a host graph H. The problem is primarily considered for several guest graphs (stars, paths and cycles) and host graphs (arbitrary graphs, planar …
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Finding Interesting Subgraphs with Guarantees
… as connectivity or a minimum density. Finding subgraphs that satisfy common constraints of interest, such as the ones above, is computationally hard in general, and state-of-the-art algorithms for many problems in network analysis are heuristic in nature. These methods are fast and usually easy …
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The Limits of Recovering Planted Subgraphs
… in terms of a variational formula over pairs of subgraphs of H, and is inspired by the celebrated subgraph expectation thresholds from probabilistic combinatorics [KK07]. Furthermore, we give a polynomial-time description of the optimizers of this variational problem. This allows one to …
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On Induced Subgraphs, Degree Sequences, and Graph Structure
Finally, we define the A4-structure H of a graph G to be the 4-uniform hypergraph on the vertex set of G where four vertices comprise an edge in H if and only if they form the vertex set of an alternating 4-cycle in G. Our definition is a variation of the notion of the P4-structure, a hypergraph …
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Efficient Computation of Cohesive Subgraphs in Uncertain Bipartite Graphs
Bipartite graphs are extensively used to model relationships between two different types of entities. In many real-world bipartite graphs, relationships are naturally uncertain due to various reasons such as data noise, measurement error and imprecision of data, leading to uncertain bipartite …
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Forbidden substructures: induced subgraphs, Ramsey games, and sparse hypergraphs
… combinatorics with respect to forbidden induced subgraphs, forbidden colored subgraphs, and forbidden subgraphs. In Chapter 2, we determine exactly which graphs H have the property that almost every H-free graph has a vertex partition into k cliques and independent sets and provide a …
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Biological applications for de Bruijn subgraphs and interval group testing
… focuses on biological applications for de Bruijn subgraphs, while the second, more theoretical, presents a study on Interval Group Testing in the presence of erroneous test outcomes. Although the subjects of both parts are from the computational viewpoint completely distinct, their motivations are …
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A Novel Method to Detect Functional Subgraphs in Biomolecular Networks
Several biomolecular pathways governing the control of cellular processes have been discovered over the last several years. Additionally, advances resulting from combining these pathways into networks have produced new insights into the complex behaviors observed in cell function assays. …
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Sufficient conditions for the existence of specified subgraphs in graphs
… Erdős. In Chapter 3, we rephrase the problem of subgraphs in the language of graph packing. Two graphs G and G' pack if G is a subgraph of the complement of G' or, equivalently, if G' is a subgraph of the complement of G. Graph packing is a restatement of the subgraph problem that does not …
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Sublinear-time algorithms for counting star subgraphs with applications to join selectivity estimation
… algorithms for approximating the number of star subgraphs, bypassing the lower bounds in this prior work. For example, in the regime where ... , our upper bound is ... in contrast to their ... lower bound when no random edge queries are available. In addition, we consider the problem of counting …
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Embedding Problems for Graphs and Hypergraphs
… consider the substructures consisting of fixed subgraphs or families of subgraphs, perfect graph packings and spanning subgraphs. In the case of hypergraphs we consider the substructure consisting of a hypergraph whose order is linear in the order of the large hypergraph. I will show how these …
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Unstable Communities in Network Ensembles
… is usually formulated as one of computing dense subgraphs (communities) that are frequent, i.e., appear in many graphs in the ensemble. In this thesis, we seek to find "unstable communities" which are the antithesis of frequent, dense subgraphs. Informally, an unstable community is a set of nodes …
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The Minimum Rank Problem Over Finite Fields
… 2. We also list all 62 such minimal forbidden subgraphs and show that many of these are minimal forbidden subgraphs for any field. Our second main result is a structural characterization of all graphs having minimum rank at most k for any k over any finite field. This characterization leads to …
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Algorithmic Computer Reconstructions of Stalactite Vaults - Muqarnas - in Islamic Architecture
… The main task is then to find all directed subgraphs corresponding to a muqarnas design for which a three--dimensional muqarnas representation is possible. We can construct three--dimensional computer reconstructions directly from the directed subgraphs. An algorithm is developed for …
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Dense subgraph detection on multi-layered networks
… of the existing methods aim to discover dense subgraphs within a single network, or within a multi-view network consisting of a common set of nodes. However, many real-world applications can be better modeled as multi-layered networks, where nodes and their dependencies vary across the …
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Inducibility and Subgraph Density Problems in Graphs
… consider the number of (not necessarily induced) subgraphs of G that are isomorphic to F, while in others we only consider the induced subgraphs of G.
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Interpretable Network Representations
… the spectral moments of the network and its subgraphs.<p>We demonstrate that network shapes can capture various properties of not only the network, but also its subgraphs. For instance, they can provide the distribution of subgraphs within a network, e.g., what proportion of subgraphs are …
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