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Related papers: Lov\'asz theta type norms and Operator Systems

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This paper addresses the behavior of the Lov\'asz number for dense random circulant graphs. The Lov\'asz number is a well-known semidefinite programming upper bound on the independence number. Circulant graphs, an example of a Cayley graph,…

Lov\'asz (1967) showed that two finite relational structures A and B are isomorphic if, and only if, the number of homomorphisms from C to A is the same as the number of homomorphisms from C to B for any finite structure C. Soon after,…

Logic in Computer Science · Computer Science 2022-09-05 Anuj Dawar , Tomáš Jakl , Luca Reggio

A homomorphism from a graph $X$ to a graph $Y$ is an adjacency preserving mapping $f:V(X) \rightarrow V(Y)$. We consider a nonlocal game in which Alice and Bob are trying to convince a verifier with certainty that a graph $X$ admits a…

Quantum Physics · Physics 2016-09-21 Laura Mančinska , David E. Roberson

Lov\'asz (1967) showed that two graphs $G$ and $H$ are isomorphic if and only if they are homomorphism indistinguishable over the class of all graphs, i.e. for every graph $F$, the number of homomorphisms from $F$ to $G$ equals the number…

Combinatorics · Mathematics 2025-03-13 Martin Grohe , Gaurav Rattan , Tim Seppelt

We show that the groupoids of two directed graphs are isomorphic if and only if the two graphs are orbit equivalent by an orbit equivalence that preserves isolated eventually periodic points. We also give a complete description of the…

Dynamical Systems · Mathematics 2018-10-08 Toke Meier Carlsen , Marius Lie Winger

Graphs are fundamental objects that find widespread applications across computer science and beyond. Graph Theory has yielded deep insights about structural properties of various families of graphs, which are leveraged in the design and…

Data Structures and Algorithms · Computer Science 2023-08-30 Rachit Nimavat

In this paper, we present two main results. First, by only one conjecture (Conjecture 2.9) for recognizing a vertex symmetric graph, which is the hardest task for our problem, we construct an algorithm for finding an isomorphism between two…

Data Structures and Algorithms · Computer Science 2017-06-29 Caishi Fang

Learning a graph topology to reveal the underlying relationship between data entities plays an important role in various machine learning and data analysis tasks. Under the assumption that structured data vary smoothly over a graph, the…

Machine Learning · Statistics 2023-08-23 Xingyue Pu , Tianyue Cao , Xiaoyun Zhang , Xiaowen Dong , Siheng Chen

Graph is an abstract representation commonly used to model networked systems and structure. In problems across various fields, including computer vision and pattern recognition, and neuroscience, graphs are often brought into comparison (a…

Optimization and Control · Mathematics 2022-03-04 Quoc Van Tran , Hyo-Sung Ahn

Determining whether two graphs are structurally identical is a fundamental problem with applications spanning mathematics, computer science, chemistry, and network science. Despite decades of study, graph isomorphism remains a challenging…

Computational Physics · Physics 2026-04-10 Sara Najem , Amer E. Mouawad

Data analysts commonly utilize statistics to summarize large datasets. While it is often sufficient to explore only the summary statistics of a dataset (e.g., min/mean/max), Anscombe's Quartet demonstrates how such statistics can be…

Computational Geometry · Computer Science 2019-11-06 Hang Chen , Vahan Huroyan , Utkarsh Soni , Yafeng Lu , Ross Maciejewski , Stephen Kobourov

Many real life networks present an average path length logarithmic with the number of nodes and a degree distribution which follows a power law. Often these networks have also a modular and self-similar structure and, in some cases -…

Statistical Mechanics · Physics 2009-02-26 Alicia Miralles , Lichao Chen , Zhongzhi Zhang , Francesc Comellas

We give a linear-time algorithm that checks for isomorphism between two 0-1 matrices that obey the circular-ones property. This algorithm leads to linear-time isomorphism algorithms for related graph classes, including Helly circular-arc…

Data Structures and Algorithms · Computer Science 2013-09-18 Andrew R. Curtis , Min Chih Lin , Ross M. McConnell , Yahav Nussbaum , Francisco J. Soulignac , Jeremy P. Spinrad , Jayme L. Szwarcfiter

Measurement incompatibility--the impossibility of jointly measuring certain quantum observables--is a fundamental resource for quantum information processing. We develop a graph-theoretic framework for quantifying this resource for large…

Quantum Physics · Physics 2025-11-21 Daniel McNulty

It is unknown whether two graphs can be tested for isomorphism in polynomial time. A classical approach to the Graph Isomorphism Problem is the d-dimensional Weisfeiler-Lehman algorithm. The d-dimensional WL-algorithm can distinguish many…

Combinatorics · Mathematics 2010-12-10 Harm Derksen

The graph isomorphism problem is considered. We assign modified $n$-variable characteristic polynomials for graphs and reduce the graph isomorphism problem to the problem of the polynomials isomorphism. It is required to find out, is there…

Discrete Mathematics · Computer Science 2024-10-18 Alexander Prolubnikov

An explicit algorithm is presented for testing whether two non-directed graphs are isomorphic or not. It is shown that for a graph of n vertices, the number of n independent operations needed for the test is polynomial in n. A proof that…

Data Structures and Algorithms · Computer Science 2007-05-23 Moshe Schwartz

We study the relationship between unit-distance representations and Lovasz theta number of graphs, originally established by Lovasz. We derive and prove min-max theorems. This framework allows us to derive a weighted version of the…

Optimization and Control · Mathematics 2018-01-30 Marcel K. de Carli Silva , Levent Tunçel

We provide a criterion to distinguish two graphs which are indistinguishable by $2$-dimensional Weisfeiler-Lehman algorithm for almost all graphs. Haemers conjectured that almost all graphs are identified by their spectrum. Our approach…

Combinatorics · Mathematics 2025-11-21 Wei Wang , Da Zhao

Lov\'asz (1967) showed that two graphs $G$ and $H$ are isomorphic if, and only if, they are homomorphism indistinguishable over all graphs, i.e., $G$ and $H$ admit the same number of number of homomorphisms from every graph $F$.…

Combinatorics · Mathematics 2026-01-27 Daniel Neuen , Tim Seppelt