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We describe proper correspondences from graph C*-algebras to arbitrary C*-algebras by K-theoretic data. If the target C*-algebra is a graph C*-algebra as well, we may lift an isomorphism on a certain invariant to correspondences back and…

Operator Algebras · Mathematics 2025-06-25 Rasmus Bentmann , Ralf Meyer

We describe a correspondence between GL_n-invariant tensors and graphs, and show how this correspondence accomodates various types of symmetries and orientations.

Representation Theory · Mathematics 2009-08-12 Martin Markl

Motivated by very large-scale communication networks, we newly introduce exponentiation of graphs. Using the exponential operation on graphs, we can construct various graphs of multi-exponential order with logarithmic diameter. We show that…

Combinatorics · Mathematics 2025-01-28 Toru Hasunuma

We report on work in progress on 'nested term graphs' for formalizing higher-order terms (e.g. finite or infinite lambda-terms), including those expressing recursion (e.g. terms in the lambda-calculus with letrec). The idea is to represent…

Logic in Computer Science · Computer Science 2015-05-28 Clemens Grabmayer , Vincent van Oostrom

We give a new proof of K\"onig's theorem and generalize the Gallai-Edmonds decomposition to balanced hypergraphs in two different ways. Based on our decompositions we give two new characterizations of balanced hypergraphs and show some…

Combinatorics · Mathematics 2009-10-23 Robert Scheidweiler , Eberhard Triesch

Many real-world phenomena are naturally modeled by graphs and networks. However, classical graph models are often limited to pairwise interactions and may not adequately capture the richer structures that arise in practice. Higher-order…

Social and Information Networks · Computer Science 2026-05-18 Takaaki Fujita , Florentin Smarandache

This paper is a short introduction to the theory of tangles, both in graphs and general connectivity systems. An emphasis is put on the correspondence between tangles of order k and k-connected components. In particular, we prove that there…

Discrete Mathematics · Computer Science 2016-02-16 Martin Grohe

We use category-theoretic techniques to provide two proofs showing that for a higher-rank graph $\Lambda$, its cubical (co-)homology and categorical (co-)homology groups are isomorphic in all degrees, thus answering a question of Kumjian,…

Operator Algebras · Mathematics 2019-02-12 Elizabeth Gillaspy , Jianchao Wu

In this paper we extend and prove in detail the Finite Rank Theorem for connection matrices of graph parameters definable in Monadic Second Order Logic with counting (CMSOL) from B. Godlin, T. Kotek and J.A. Makowsky (2008) and J.A.…

Logic in Computer Science · Computer Science 2015-07-01 Tomer Kotek , Johann A. Makowsky

In this note we propose an $\omega$-operadical way to prove the existence of the $\omega$-graph of the $\omega$-graphs and the reflexive $\omega$- graph of the reflexive $\omega$-graphs.

K-Theory and Homology · Mathematics 2013-02-28 Camell Kachour

In this paper, a function on any pair of graphs is defined whose properties are similar to the properties of dot product in vector space. This function enables us to define graph orthogonality and, also, a new metric on isomorphism classes…

Combinatorics · Mathematics 2018-10-23 Ameneh Farhadian

We introduce a new method of expressing a $k$-graph $C^*$-algebra as a Cuntz-Pimsner algebra. Kumjian, Pask, and Sims have done this directly, using a linking algebra approach and a $(k-1)$-graph algebra. This can be iterated downward. Our…

Operator Algebras · Mathematics 2026-04-22 Valentin Deaconu , Menevşe Eryüzlü Paulovicks , S. Kaliszewski , John Quigg

Stochastic Kronecker graphs are a model for complex networks where each edge is present independently according the Kronecker (tensor) product of a fixed matrix k-by-k matrix P with entries in [0,1]. We develop a novel correspondence…

Combinatorics · Mathematics 2015-04-02 Mary Radcliffe , Stephen J. Young

In this paper, we use the theory of Riordan matrices to introduce the notion of a Riordan graph. The Riordan graphs are a far-reaching generalization of the well known and well studied Pascal graphs and Toeplitz graphs, and also some other…

Combinatorics · Mathematics 2019-04-16 Gi-Sang Cheon , Ji-Hwan Jung , Sergey Kitaev , Seyed Ahmad Mojallal

In this paper, we develop a $\times$-homotopy fundamental groupoid for graphs, and show a functorial relationship to the 2-category of graphs. We further explore the fundamental groupoid of graph products and develop a groupoid product…

Combinatorics · Mathematics 2020-07-14 Tien Chih , Laura Scull

New criteria for which Cayley graphs of cyclic groups of any order can be completely determined--up to isomorphism--by the eigenvalues of their adjacency matrices is presented. Secondly, a new construction for pairs of nonisomorphic Cayley…

Combinatorics · Mathematics 2009-04-14 Julia Brown

We define a new mathematical structure ( graph quantum group) which combines the tower of algebras associated with a graph ${\cal G}$ and the structure of a Hopf algebra {\cal A}. In this structure Ocneanu's string operators become Hopf…

High Energy Physics - Theory · Physics 2007-05-23 C. Gomez , G. Sierra

We prove a Stepanov differentiability type theorem for intrinsic graphs in sub-Riemannian Heisenberg groups.

Metric Geometry · Mathematics 2025-07-08 Marco Di Marco , Andrea Pinamonti , Davide Vittone , Kilian Zambanini

After a somewhat rocky start, geometry and topology have established a foothold in machine learning. Message passing, either on graphs or higher-order complexes, is one of the main drivers of geometric deep learning, and paradigms that were…

Machine Learning · Computer Science 2026-05-11 Bastian Rieck

This paper presents the first use of graph neural networks (GNNs) for higher-order proof search and demonstrates that GNNs can improve upon state-of-the-art results in this domain. Interactive, higher-order theorem provers allow for the…

Machine Learning · Computer Science 2019-09-16 Aditya Paliwal , Sarah Loos , Markus Rabe , Kshitij Bansal , Christian Szegedy