New graph types help identify complex relationships.
problem Understanding complex relationships in data.
method Introducing separable and essentially separable graphs to characterize and identify graphical models.
result Developed algorithms to identify equivalence classes of essentially separable graphs.
Classifies essential annuli in a genus two handlebody exterior.
problem Classifying essential annuli in a genus two handlebody exterior.
method Building on JSJ-graph classification and essential annuli classification.
result Characterizes the numbers of different types of essential annuli in an infinite family.
Automorphisms of fine curve graphs match surface homeomorphisms for planar surfaces.
problem Understanding automorphisms of fine curve graphs on surfaces.
method Analyzing vertices and edges of fine curve graphs to match with surface homeomorphisms.
result Automorphism group of fine curve graphs is naturally isomorphic to the homeomorphism group of boundaryless planar surfaces with at least 7 punctures.
Essential embeddings of metric graphs on hyperbolic surfaces are constructed and studied.
problem Embedding metric graphs on hyperbolic surfaces with negative Euler characteristic.
method Construction of essential embeddings and study of minimal embeddings.
result Formula to compute essential genus and method for explicit essential embedding.
Study restricts causal graphs with expert knowledge.
problem Restricting causal graphs to include expert orientation knowledge.
method Prove properties, present new orientation rules, develop algorithms.
result Shows how to uniquely represent restricted essential ancestral graphs.
The paper develops formulas to count sizes of Markov equivalence classes of DAGs.
problem Measuring uncertainty and complexity in causal learning from DAGs.
method Introducing core graphs and deriving polynomial size formulas via symbolic computation.
result Efficient formulas for counting sizes of Markov equivalence classes of DAGs.
Let T be a graph in a compact, orientable 3--manifold M and let Γ be a subgraph. T can be placed in bridge position with respect to a Heegaard surface H. We show that if H is what we call (T,Γ)-c-weakly reducible in the complement of T then either a "degenerate" situation occurs or H can be untelescop…
The study embeds graphs on translation surfaces, proving essential-systolic embeddings and estimating surface genera.
problem Embedding graphs on translation surfaces with specific properties.
method Proving essential-systolic embeddings and estimating surface genera.
result Finite graphs admit essential-systolic embeddings on translation surfaces with estimated genera.
Study shows surfaces without certain curves have infinite orbit graph.
problem Characterizing surfaces with specific curve properties.
method Utilized tools from mapping class group geometry.
result Infinite-invariance index 1 surfaces lack good curve graphs.
New findings on hyperbolicity of fine curve graphs and their subgraphs.
problem Investigating hyperbolicity of fine curve graphs and their subgraphs.
method Analyzing large subgraphs of fine curve graphs and computing distances in specific cases.
result Large subgraphs of fine curve graphs contain flats of every finite dimension, indicating they are not hyperbolic.
Essential curves in certain graph manifolds imply non-linear groups.
problem Non-linear groups in graph manifolds with specific curvature properties.
method Analyzing essential curves on JSJ tori and their representations.
result Groups in the specified graph manifolds are not linear over any field.
Designs interventions to learn causal graphs with minimum cost.
problem Learning causal graphs with minimum intervention cost.
method Prove NP-hardness, develop greedy and constrained algorithms.
result Achieve nearly optimal intervention design for sparse graphs.
We study the existence and uniqueness of the heat kernel on infinite, locally finite, connected graphs. For general graphs, a uniqueness criterion, shown to be optimal, is given in terms of the maximal valence on spheres about a fixed vertex. A sufficient condition for non-uniqueness is also presented. Furthermore, we …
The paper describes the K-theory of C∗-algebras of locally finite graphs.
problem Computing the K-theory of C∗-algebras of locally finite graphs. method Using a directed graph representation and Cuntz-Krieger algebra, the paper computes the K-theory of C∗(Γ). result The K-theory of C∗(Γ) is determined by the graph's genus, number of ends, and dead-ends. 3D Schoenflies theorem for simply-connected 2-complexes.
problem Embedding simply-connected 2-complexes in 3-space uniquely.
method Proving a 3-dimensional Schoenflies theorem for 3-connected link graphs.
result Essentially unique locally flat embedding into 3-sphere.
Essential tori in certain 3-manifolds are missed by ideal points in character varieties.
problem Essential tori in 3-manifolds are not detected by ideal points in character varieties.
method Infinite families of 3-manifolds are constructed to show the existence of essential tori not detected by ideal points in character varieties over any algebraically closed field.
result Essential tori in 3-manifolds are missed by ideal points in character varieties over any algebraically closed field.
We show that given a trivalent graph in S3, either the graph complement contains an essential almost meridional planar surface or thin position for the graph is also bridge position. This can be viewed as an extension of a theorem of Thompson to graphs. It follows that any graph complement always contains a useful p…
Algorithm morphs graphs on hyperbolic surfaces.
problem Morphing graphs on hyperbolic surfaces.
method Generalization of Tutte's spring embedding theorem.
result First algorithm for morphing graphs on hyperbolic surfaces.
Characterizes Bayesian networks up to unconditional equivalence.
problem Characterizing Bayesian networks up to unconditional equivalence.
method Transformational characterization via undirected graphs and specified moves.
result Two DAGs are in the same UEC if and only if one can be transformed into the other via a finite sequence of moves.
Characterizes quasiconformal homeomorphisms on surfaces.
problem Understanding the group of quasiconformal homeomorphisms on surfaces.
method Combinatorial characterization of quasiconformal homeomorphisms via graphs of essential quasicircles.
result Quasiconformal homeomorphisms are automorphisms of a graph of essential quasicircles on a surface.
Study shows stable graphs in Heisenberg group are essentially planes.
problem Characterizing stable graphs in the Heisenberg group.
method Analyzes Sobolev intrinsic graphs in the Heisenberg group with sub-Riemannian area stability.
result Stable graphs are cosets of two-dimensional subgroups.
Extends graph degree theorem to simplicial closure of Auter space.
problem Connectivity of graphs in Auter space.
method Defines degree for simplicial closure, extends Hatcher-Vogtmann theorem.
result Simplicial closure of Auter space is (d-1)-connected for degree d.
New proof for knot state-sum formula using bijection between states.
problem Proving a knot state-sum formula for colored Jones polynomial.
method Established bijection between states on arc-graph and bichromatic digraph, used flow property of R-matrix.
result Two state models are essentially the same, extending formula to links.
Let M be a compressionbody containing a graph T (with at least one edge) such that \boundary_+ M is parallel to the union of T and \boundary_- M. We extend methods of Hayashi and Shimokawa to classify bridge surfaces for T. The results of this paper are used in later work to show that if a bridge surface for a graph in…
New matrix reveals cluster info in sparse directed graphs.
problem Analyzing cluster information in directed graphs.
method Proposed complex non-backtracking matrix integrating Hermitian adjacency matrix and non-backtracking matrix properties.
result The complex non-backtracking matrix holds cluster information, especially for sparse directed graphs.
Automorphism group of nonorientable surface curve graph matches surface homeomorphisms.
problem Identifying automorphisms of nonorientable surface curve graphs.
method Using Bowden, Hensel, and Webb's fine curve graph and Long, Margalit, Pham, Verberne, and Yao's proof as a foundation.
result Automorphism group of nonorientable surface curve graph is isomorphic to the surface's homeomorphism group.
We study real nonsingular projective cubic fourfolds up to deformation equivalence combined with projective equivalence and prove that they are classified by the conjugacy classes of involutions induced by the complex conjugation in the middle homology. Moreover, we provide a graph whose vertices represent the equivale…
In his PhD thesis, Abrams proved that, for a natural number n and a graph G with at least n vertices, the n-strand configuration space of G deformation retracts to a compact subspace, the discretized n-strand configuration space, provided G satisfies two conditions: each path between distinct essential vertices (vertic…
We define a pseudo-inverse for line graphs using linear integer programming.
problem Not all graphs have a corresponding root graph, making the line graph operation non-invertible.
method Propose a linear integer program to edit the smallest number of edges in the line graph to recover a root graph.
result The pseudo-inverse operation is well-behaved and works in practice as shown by empirical experiments.
The fine curve graph is hyperbolic and contains all countable graphs as induced subgraphs.
problem Characterizing the structure and properties of fine curve graphs.
method Analyzing the hyperbolicity and induced subgraph properties of fine curve graphs and their direct limits.
result The finitary curve graph has diameter 2, contains every countable graph as an induced subgraph, and has the homeomorphism group of the surface as its automorphism group.
Generalizing Milnor's result that an FTC (finite total curvature) knot has an isotopic inscribed polygon, we show that any two nearby knotted FTC graphs are isotopic by a small isotopy. We also show how to obtain sharper constants when the starting curve is smooth. We apply our main theorem to prove a limiting result f…
We define transit clusters to simplify causal diagrams and preserve their essential properties.
problem Clustering variables in causal diagrams can alter essential properties of causal effects.
method We define transit clusters and provide an algorithm to find them, ensuring they preserve causal effect identifiability.
result Transit clusters simplify causal effect identification and maintain their essential properties.
New algorithms verify and search causal graphs with minimal interventions.
problem Recovering causal graphs from interventional data.
method Characterization of minimal intervention sets for verification, and adaptive graph separator algorithm for search.
result First provable algorithms for efficient verification and search of causal graphs.
We establish bounds on the KL divergence between two multivariate Gaussian distributions in terms of the Hamming distance between the edge sets of the corresponding graphical models. We show that the KL divergence is bounded below by a constant when the graphs differ by at least one edge; this is essentially the tighte…
Upper bounds for Laplace eigenvalues on non-compact manifolds.
problem Proving upper bounds for Laplace eigenvalues on non-compact manifolds.
method Using geometric data and properties of Cartan-Hadamard manifolds.
result Upper bounds for Laplace eigenvalues in terms of k2 and specific geometric data. In this thesis, we analyze the stochastic completeness of a heat kernel on graphs which is a function of three variables: a pair of vertices and a continuous time, for infinite, locally finite, connected graphs. For general graphs, a sufficient condition for stochastic completeness is given in terms of the maximum vale…
Develops a method to efficiently learn causal DAGs using directed clique trees.
problem Efficiently learning causal DAGs in the presence of large cliques.
method Decomposes DAGs into independently orientable components using directed clique trees and designs a two-phase intervention algorithm.
result Proves that the number of single-node interventions necessary to orient any DAG in an EC is at least the sum of half the size of the largest cliques in each chain component of the essential graph.
The study proves unique harmonic functions and combinatorial properties of vertex-transitive graphs.
problem Proving combinatorial properties of vertex-transitive graphs.
method Using harmonic functions and quasi-isometry to R, proving uniqueness and combinatorial results. result Connective constant of non-degenerate vertex-transitive graphs is at least the golden mean.
We introduce a class of spaces, called real cubings, and study the stucture of groups acting nicely on these spaces. Just as cubings are a natural generalisation of simplicial trees, real cubings can be regarded as a natural generalisation of real trees. Our main result states that a finitely generated group G acts n…
This paper analyzes various graph clustering methods and their applications.
problem Dividing graphs into homogeneous groups for diverse applications.
method Traditional and deep learning-based clustering methods are compared.
result Deep learning techniques improve clustering accuracy.
The paper proves drilled bundles over graphs are virtually special cubulable.
problem Proving drilled bundles over graphs are virtually special cubulable.
method Starting with a Gromov-hyperbolic surface bundle, drilling out essential curves, and using relative hyperbolicity and Wise's theorem.
result Proves drilled bundles over graphs are virtually special cubulable.
Spektral simplifies graph neural networks with TensorFlow and Keras.
problem Building graph neural networks efficiently.
method Open-source library implementing various graph neural network methods.
result Performance of implemented methods in node, graph, and graph regression tasks.
Graph neural networks are vulnerable to adversarial attacks that manipulate graph structure.
problem Vulnerability of graph neural networks to adversarial attacks.
method Meta-learning approach to solve bilevel optimization problem of training-time attacks.
result Small graph perturbations can significantly degrade graph neural network performance.
Graph neural networks improve cold start for new items in recommender systems.
problem Cold start problem for new items in recommender systems.
method Item hierarchy graphs and bespoke graph neural network architecture.
result Our method achieves better forecasting quality than state-of-the-art with comparable computational time.
Graph continuous operators become Riesz continuous after multiplication by unitary operators.
problem Characterizing Riesz continuity of graph continuous operators.
method Multiplication by unitary operators to transform graph continuity to Riesz continuity.
result The index of graph continuous families of Fredholm operators coincides with N. Ivanov's index.
The paper solves graph realization problems for Reeb graphs of Morse functions.
problem Realizing graphs as Reeb graphs with specific preimage configurations.
method Constructing Morse functions with prescribed preimages.
result Solved realization problems for certain types of graphs.
Counterexamples to a conjecture on ribbon graph genus changes were found and proven.
problem A conjecture on genus changes in ribbon graphs was formulated and disproven.
method A family of counterexamples was found and proven.
result Essentially, the counterexamples found by Qi Yan and Xian'an Jin are the only ones.
Adaptive graph convolution improves attributed graph clustering performance.
problem Joint modeling of graph structures and node attributes is challenging.
method Adaptive graph convolution that captures global cluster structure and selects appropriate order for different graphs.
result Empirical results show our method compares favorably with state-of-the-art methods.