Events by month

Title: Four types of integrality on mixed Cayley graphs over abelian groups

Speaker: Monu Kadyan Affiliation: Indian Institute of Technology Guwahati Location: Please contact Sabrina Lato for Zoom link

Abstract: A mixed graph is called H-integral (resp. HS-integral) if the eigenvalues of its Hermitian-adjacency matrix (resp. Hermitian-adjacency matrix of second kind) are integers.

Title: The heroes of digraphs: coloring digraphs with forbidden induced subgraphs

Speaker: Alvaro Carbonero Affiliation: University of Waterloo Location: MC 5479

Abstract: The chromatic number is one of the most studied graph invariants in graph theory. $\chi$-boundedness, for instance, studies the induced subgraphs present in graphs with large chromatic number and small clique number. Neumann-Lara introduced an analog directed version of this graph invariant: the dichromatic number of digraphs.

Title: Quantum Algorithms and Mutually Unbiased Bases

Speaker: Andrew Jena Affiliation: University of Waterloo Location: Please contact Sabrina Lato for Zoom link

Abstract: Mutually unbiased bases are fundamental to quantum information theory, showing up in quantum key distribution, quantum error correction, and quantum entanglement measures. They likewise might be familiar to algebraic graph theorists, thanks to their connection to equiangular lines and association schemes.

Title: Sets that Support a Joint Distribution

Speaker: Peter Winkler Affiliation: Dartmouth College Location: MC 5501 or contact Eva Lee for Zoom link

Abstract: Given a closed set on the plane and two probability distributions on the real line, when are there random variables with the given distributions whose joint distribution is supported by the given set?

Title: A Primal-Dual Extension of the Goemans and Williamson Algorithm for Weighted Fractional Cut Cover

Speaker: Nathan Benedetto Proenca Affiliation: University of Waterloo Location: Please contact Sabrina Lato for Zoom link

Abstract: A cut in a graph G = (V, E) is a set of edges which has one endpoint in S, for a given subset S of V. The fractional cut-covering number is the optimal value of a linear programming relaxation for the problem of covering each edge by a set of cuts. Beyond its role as part of Šámal's work on cut continuous functions, this graph parameter also arises as the gauge dual of the maximum cut problem.