Events

Filter by:

Limit to events where the first date of the event:
Date range
Limit to events where the first date of the event:
Limit to events where the title matches:
Limit to events where the type is one or more of:
Limit to events tagged with one or more of:
Limit to events where the audience is one or more of:
Monday, June 5, 2023 10:00 am - 10:00 am EDT (GMT -04:00)

URA Seminar - Anirban Chowdhury

Title: Approximation algorithms for dense quantum Hamiltonians using convex relaxations

Speaker: Anirban Chowdhury
Affiliation: University of Waterloo
Location: MC 5479

Abstract: Computing ground-state energy and partition functions for quantum Hamiltonian systems are problems of broad applicability in physics. These are also natural generalizations of well-studied classical computational tasks such as maximum constraint satisfaction and computing partition functions of Ising models. In this talk, I will present new classical approximation algorithms for these problems in the case of dense quantum Hamiltonians.

Monday, June 5, 2023 11:30 am - 11:30 am EDT (GMT -04:00)

Algebraic Graph Theory - Martin Stefanak

Title: Quantum walk state transfer on a hypercube

Speaker: Martin Stefanak
Affiliation: Czech Technical University
Location: Please contact Sabrina Lato for Zoom link

Abstract: We investigate state transfer on a hypercube by means of a quantum walk where the sender and the receiver vertices are marked by weighted loops.

Monday, June 5, 2023 1:00 pm - 1:00 pm EDT (GMT -04:00)

C&O Reading Group - Ian DeHaan

Title: Extended Formulations for the Colonel Blotto Game

Speaker: Ian DeHaan
Affiliation: University of Waterloo
Location: MC 6029

Abstract: Suppose you want to replace Doug Ford as premier. To beat him, you need to win as many seats as possible. You have some finite amount of resources to allocate across all seats - if you spend more on a seat than Ford does, you will win that seat. How should you allocate your resources to maximize your expected number of seats?

Friday, June 9, 2023 3:30 pm - 3:30 pm EDT (GMT -04:00)

Tutte Colloquium - Shi Li

Title: Online Unrelated-Machine Load Balancing and Generalized Flow with Recourse

Speaker: Shi Li
Affiliation: University at Buffalo
Location: MC 5501

Abstract: I will present the online algorithms for unrelated-machine load balancing problem with recourse.  First, we shall present a (2+\epsilon)-competitive algorithm for the problem with O_\epsilon(\log n) amortized recourse per job.

Monday, June 12, 2023 11:30 am - 11:30 am EDT (GMT -04:00)

Algebraic Graph Theory - William Linz

Title: L-systems and the Lovasz number

Speaker: William Linz
Affiliation: University of South Carolina
Location: Please contact Sabrina Lato for Zoom link

Abstract: For positive integers n and k, an L-system is a collection of k-uniform subsets of a set of size n whose pairwise intersection sizes all lie in in the set L. The maximum size of an L-system is equal to the independence number of a certain union of graphs in the Johnson scheme. The Lovasz number is a semidefinite programming approximation of the independence number of a graph. In this talk, we survey the relationship between the maximum size of an L-system and the Lovasz number, illustrating examples both where the Lovasz number is a good approximation and where it is a bad approximation.

Monday, June 12, 2023 2:30 pm - 2:30 pm EDT (GMT -04:00)

URA Seminar - Ricardo Fukasawa

Title: Research in Applications

Speaker: Ricardo Fukasawa
Affiliation: University of Waterloo
Location: MC 5479

Abstract: In this talk I will present my personal experiences in doing research involving applications. I will go over some of my work, presenting some of the key aspects that are involved, and trying to take stock of a few lessons learned.

Thursday, June 15, 2023 1:00 pm - 1:00 pm EDT (GMT -04:00)

Algebraic Combinatorics - Matthew Satriano

Title: Monomial ideals, Galois closures, and Hilbert schemes of points

Speaker: Matthew Satriano
Affiliation: University of Waterloo
Location: MC 5501 and Zoom - please contact Oliver Pechenik for the Zoom link

Abstract: Manjul Bhargava and the speaker introduced a functorial Galois closure operation for finite-rank ring extensions, generalizing constructions of Grothendieck and Katz-Mazur. In this talk, we use Galois closures to construct new components of Hilbert schemes of points, which are fundamental objects in algebraic geometry whose component structure is largely mysterious. We answer a 35 year old open problem posed by Iarrobino by constructing an infinite family of low dimensional components. This talk is based on joint work with Andrew Staal. No prior knowledge of Hilbert schemes will be assumed.

Friday, June 16, 2023 3:30 pm - 3:30 pm EDT (GMT -04:00)

Tutte Colloquium - Ting Kei Pong

Title: Error bounds for conic feasibility problems: case studies on the exponential cone

Speaker: Ting Kei Pong
Affiliation: The Hong Kong Polytechnic University
Location: MC 5501

Abstract: Conic feasibility problems naturally arise from linear conic programming problems. An understanding of error bounds for these problems is instrumental in the design of termination criteria for conic solvers and the study of convergence rate of algorithms.

Monday, June 19, 2023 11:30 am - 11:30 am EDT (GMT -04:00)

Algebraic Graph Theory - Sung Song

Title: Partial geometric designs, directed strongly regular graphs, and association scheme

Speaker: Sung Song
Affiliation: Iowa State University
Location: Please contact Sabrina Lato for Zoom link

Abstract: A partial geometric design with parameters $(v, b, k, r; \alpha, \beta)$ is a tactical configuration $(P, \mathcal{B})$ (with $|P|=v$, $|\mathcal{B}|=b$, every point $p\in P$ belonging to $r$ blocks, and every block $B\in\mathcal{B}$ consisting of $k$ points) satisfying the property:

{for any pair $(p, B)\in P\times \mathcal{B}$, the number of flags $(q, C)$ with $q\in B$ and $C\ni p$ equals to $\alpha  \mbox{ if } p\notin B$ and to $\beta  \mbox{ if } p\in B$.}

Neumaier studied partial geometric designs in detail in his article, ``$t\frac12$-designs," [JCT A {\bf 28}, 226-248 (1980)]. He investigated their connection with strongly-regular graphs and gave various characterizations of partial geometries, bipartite graphs, symmetric 2-designs, and transversal designs in terms of partial geometric designs.