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Proceedings ArticleDOI

Isomorphism of graphs with bounded eigenvalue multiplicity

TLDR
Two polynomial time algorithms are described which test isomorphism of undirected graphs whose eigenvalues have bounded multiplicity, if X and Y are graphs of eigenvalue multiplicity m.
Abstract
We investigate the connection between the spectrum of a graph, i.e. the eigenvalues of the adjacency matrix, and the complexity of testing isomorphism. In particular we describe two polynomial time algorithms which test isomorphism of undirected graphs whose eigenvalues have bounded multiplicity. If X and Y are graphs of eigenvalue multiplicity m, then the isomorphism of X and Y can be tested by an O(n4m+c) deterministic and by an O(n2m+c) Las Vegas algorithm, where n is the number of vertices of X and Y.

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Posted Content

Approximating uniform quantum channels

TL;DR: In this article, a uniform quantum channel QU from a finite subgroup of unitary matrices acting on the space of qubits to itself has been proposed to study the orbit equivalence of two density matrices under the action of the subgroup.
Journal ArticleDOI

The Isomorphism Problem of Power Graphs and a Question of Cameron

Bireswar Das, +2 more
- 30 May 2023 - 
TL;DR: In this paper , a polynomial time algorithm for the isomorphism problem of graphs that are defined in terms of groups, namely power graphs, the directed power graphs and the enhanced power graphs arising from finite nilpotent groups was proposed.
Journal ArticleDOI

Exact Recovery with Symmetries for the Doubly-Stochastic Relaxation

TL;DR: Graph matching, or quadratic assignment, is the problem of labeling the vertices of two graphs so that they are as similar as possible as discussed by the authors, which is NP-hard.

Eigenvalue Gaps of Random Perturbations of Large Matrices

TL;DR: In this paper , the authors apply some combinatorial tools due to Jain to control the eigenvalue gaps of a matrix M n = M + N n where M n is deterministic, symmetric with large operator norm and N n is a random symmetric matrix with subgaussian entries.

Vertex analogy testing through comparison of ordered eigenprojections: an exact polynomial-time algorithm for potentially degenerate graph isomorphism tasks.

Robert O'Shea
TL;DR: In this article , an exact method to identify analogous vertices in isomorphic graphs, through comparison of vertices ’ projections onto each eigenspace, was presented, and repeated iterations of analogy testing, and perturbation allowed recovery of an isomorphic mapping in ǫ(ǫ 4 ) time.
References
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MonographDOI

Algebraic graph theory

TL;DR: In this article, the authors introduce algebraic graph theory and show that the spectrum of a graph can be modelled as a graph graph, and the spectrum can be represented as a set of connected spanning trees.
Book

Spectra of graphs : theory and application

TL;DR: The Spectrum and the Group of Automorphisms as discussed by the authors have been used extensively in Graph Spectra Techniques in Graph Theory and Combinatory Applications in Chemistry an Physics. But they have not yet been applied to Graph Spectral Biblgraphy.
Proceedings ArticleDOI

Linear time algorithm for isomorphism of planar graphs (Preliminary Report)

TL;DR: The time bound for planar graph isomorphism is improved to O(|V|) time and the algorithm can be easily extended to partition a set of planar graphs into equivalence classes of isomorphic graphs in time linear in the total number of vertices in all graphs in the set.