Monday, October 25, 2021 — 11:30 AM EDT

Title: State transfer on graphs with twin vertices

Speaker: Hermie Monterde
Affiliation: University of Manitoba
Zoom: Contact Soffia Arnadottir

Abstract:

In this talk, we discuss algebraic and spectral properties of graphs with twin vertices that are important in quantum state transfer. We give a characterization of strong cospectrality between twin vertices, and characterize some types of state transfer that occur between them.

Friday, October 22, 2021 — 3:30 PM EDT

Title: Dyadic Linear Programming

Speaker: Ahmad Abdi
Affiliation: London School of Economics
Zoom: Please email Emma Watson

Abstract:

Most linear programming solvers use fixed-precision floating points to approximate the rational numbers. Though successful on most real-world instances, solvers sometimes run into serious issues when carrying out sequential floating-point arithmetic, due to compounded error terms. This practical limitation leads to the following theoretical problem:

Friday, October 8, 2021 — 3:30 PM EDT

Title: Induced subgraphs and treewidth

Speaker: Sophie Spirkl
Affiliation: University of Waterloo
Zoom: Please email Emma Watson

Abstract:

Treewidth, introduced by Robertson and Seymour in the graph minors series, is a fundamental measure of the complexity of a graph. While their results give an answer to the question, “what minors occur in graphs of large treewidth?,” the same question for induced subgraphs is still open. I will talk about some conjectures and recent results in this area.

Joint work with Tara Abrishami, Maria Chudnovsky, Cemil Dibek, Sepehr Hajebi, Pawel Rzazewski, Kristina Vuskovic.

Thursday, October 7, 2021 — 1:00 PM EDT

Title: Newell-Littlewood numbers

Speaker: Shiliang Gao
Affiliation: University of Illinois at Urbana-Champaign
Zoom: Contact Steve Melczer

Abstract:

The Newell-Littlewood numbers are defined in terms of the Littlewood-Richardson coefficients. Both arise as tensor product multiplicities for a classical Lie group. A. Klyachko connected eigenvalues of sums of Hermitian matrices to the saturated LR-cone and established defining linear inequalities.

Monday, October 4, 2021 — 11:30 AM EDT

Title: Four families of polynomials in spectral graph theory

Speaker: Miguel Angel Fiol Mora
Affiliation: Universitat Politècnica de Catalunya
Zoom: Contact Soffia Arnadottir

Abstract:

 In this talk we describe four families of polynomials related to the spectrum of a graph. First, some known main results involving such polynomials, such as the spectral excess theorem characterizing distance-regularity, are discussed. Second, some new results giving bounds for the $k$-independence number $\alpha_k$ of a graph are presented. In this context, we comment on some relationships between the inertia (Cvetkovi\`c) and ratio (Hoffman) bounds of $\alpha_k$.

Friday, October 1, 2021 — 3:30 PM EDT

Title: Quantum information science for combinatorial optimization

Speaker: Stephen Jordan
Affiliation: Microsoft Quantum & University of Maryland
Zoom: Please email Emma Watson

Abstract:

Due to input-output bottlenecks, quantum computers are expected to be most applicable to problems for which the quantity of data specifying the instance is small but the computational cost of finding a solution is large. Aside from cryptanalysis and quantum simulation, combinatorial optimization provides some of the best candidates for problems of real-world impact fitting these criteria. Many of these problems are NP-hard and thus unlikely to be solvable on quantum computers with polynomial worst-case time complexity.

S M T W T F S
26
27
28
29
30
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
2
3
4
5
6
  1. 2021 (93)
    1. October (6)
    2. September (12)
    3. August (6)
    4. July (10)
    5. June (12)
    6. May (7)
    7. April (9)
    8. March (13)
    9. February (8)
    10. January (10)
  2. 2020 (119)
    1. December (5)
    2. November (12)
    3. October (12)
    4. September (12)
    5. August (11)
    6. July (17)
    7. June (11)
    8. May (6)
    9. March (11)
    10. February (11)
    11. January (11)
  3. 2019 (167)
  4. 2018 (136)
  5. 2017 (103)
  6. 2016 (137)
  7. 2015 (136)
  8. 2014 (88)
  9. 2013 (48)
  10. 2012 (39)
  11. 2011 (36)
  12. 2010 (40)
  13. 2009 (40)
  14. 2008 (39)
  15. 2007 (15)