#### Contact Info

Combinatorics & Optimization

University of Waterloo

Waterloo, Ontario

Canada N2L 3G1

Phone: 519-888-4567, ext 33038

PDF files require Adobe Acrobat Reader.

Friday, March 16, 2018 3:30 PM EDT

**Title:** A George Szekeres formula for restricted partitions

Speaker: | Bruce Richmond |

Affiliation: | University of Waterloo |

Room: | MC 5501 |

**Abstract:**

We give asymptotic formulas for the number of integer partitions of n with at most j parts and having largest part at most r, say A(n,j,r). We do this also for the number of partitions of n with largest part equal to r and having exactly j parts, say C(n,j,r).

Thursday, March 15, 2018 1:30 PM EDT

**Title**: Quantum State Transfer

Speaker: | Christopher van Bommel |

Affilliation: | University of Waterloo |

Room: | MC 6486 |

**Abstract**:

Many quantum algorithms may be modeled as a quantum process occurring on a graph. We interpret quantum channels implemented by spin chains as wires for transmission of states.

Wednesday, March 14, 2018 4:00 PM EDT

**Title: Data-driven Inverse Optimization with Imperfect Information**

Speaker: | Stefan Sremac |

Affilliation: | University of Waterloo |

Room: | MC 5479 |

**Abstract:**

We continue our reading group with a paper by Kuhn et al with the same title as above.

Tuesday, March 13, 2018 4:30 PM EDT

**Title**: What's an amplituhedron?

Speaker: | Cameron Marcott |

Affilliation: | University of Waterloo |

Room: | MC 5501 |

**Abstract**:

I'll introduce the amplituhedron, focusing on why the suffix "hedron" is justified.

Monday, March 12, 2018 1:30 PM EDT

**Title:** LWE Part 1: The problem, the cryptosystem and its relationship to lattice Problems

Speaker: | Luiz Ruiz |

Affiliation: | University of Waterloo |

Room: | MC 6486 |

**Abstract:**

In this talk we will give an overview of the Learning With Errors problem,

Friday, March 9, 2018 3:30 PM EST

**Title:** Chromatic Symmetric Functions and H-Free Graphs

Speaker: | Angèle Hamel |

Affiliation: | Wilfrid Laurier University |

Room: | MC 2038 (not 5501) |

**Abstract:**

Chromatic symmetric functions are defined in terms of colourings of particular graphs. Some key conjectures in this area concern whether chromatic symmetric functions of claw-free graphs can be written in terms of other symmetric functions with positive coefficients.

Thursday, March 8, 2018 3:30 PM EST

**Title:** Claws, ω and χ: induced binary submatroids

Speaker: | Peter Nelson |

Affilliation: | University of Waterloo |

Room: | MC 5479 |

**Abstract:**

I will discuss the interplay between clique number, chromatic number, and excluding induced submatroids in the setting of binary matroids.

Thursday, March 8, 2018 1:30 PM EST

**Title:** Unitary Groups, II

Speaker: | Chris Godsil |

Affiliation: | University of Waterloo |

Room: | MC 6486 |

**Abstract:**

Actually the title should be 2 Unitary groups - I will discuss the 2-dimensional unitary groups.

Monday, March 5, 2018 3:30 PM EST

**Title:** Traveling Salesman Problems

Speaker: | William (Bill) Cook |

Affiliation: | University of Waterloo |

Room: | MC 5417 |

**Abstract:**

We discuss open research questions, both theoretical and computational, surrounding the traveling salesman problem.

Thursday, March 1, 2018 3:30 PM EST

**Title:** Counting matroids

Speaker: | Jorn van der Pol |

Affiliation: | University of Waterloo |

Room: | MC 5479 |

**Abstract:**

We discuss several recent results concerning matroid enumeration and typical properties of matroids, emphasizing the central role that sparse paving matroids play in these results.

Thursday, March 1, 2018 1:30 PM EST

**Title:** Unitary Groups

Speaker: | Chris Godsil |

Affiliation: | University of Waterloo |

Room: | MC 6486 |

**Abstract:**

Unitary groups play an important role in physics and in finite geometry. This talk, the first of two, will provide an introduction to the topic focusing on the case where the underlying field is the complex numbers.

Monday, February 26, 2018 10:30 AM EST

**Title:** Random Networks: Enumeration, Generation, and Universality

Speaker: | Pu (Jane) Gao |

Affilliation: | Monash University |

Room: | DC 1304 |

**Abstract:**

Large networks appear in almost all branches of the sciences and in everyday life, and they are often modeled by random graphs. Among the various random graph models, random graphs with specified degrees are particularly important in modelling and analyzing real-world networks.

Friday, February 16, 2018 3:30 PM EST

**Title:** Tangent Lines and the equation 28 = 7 × 4

Speaker: | Yoav Len |

Affiliation: | University of Waterloo |

Room: | MC 5501 |

**Abstract:**

I will discuss combinatorial aspects of tangent lines to curves and planar graphs. In algebraic geometry, every smooth plane curve has finitely many lines that are tangent to it at two separate points.

Thursday, February 15, 2018 3:30 PM EST

**Title:** An introduction to gammoids

Speaker: | Rutger Campbell |

Affiliation: | University of Waterloo |

Room: | MC 5479 |

**Abstract:**

A gammoid is a matroid that is defined via vertex connectivity in a graph.

Thursday, February 15, 2018 1:30 PM EST

**Title:** Mixing in Discrete-Time Quantum Walks

Speaker: | Harmony Zhan |

Affiliation: | University of Waterloo |

Room: | MC 6486 |

**Abstract:**

Discrete-time quantum walks are building blocks for quantum algorithms. There are some parameters of a quantum walk that affect the performance of a quantum algorithm, such as the (time-averaged) limiting distribution and the mixing time.

Wednesday, February 14, 2018 4:00 PM EST

**Title:** Comprehensive robust counterparts of uncertain problems

Speaker: | Sina Rezazadeh |

Affiliation: | University of Waterloo |

Room: | MC 5479 |

**Abstract:**

We continue our study of Robust Optimization by discussing the paper by Ben-Tal, Boyd and Nemirovski, "Extending scope of robust optimization: comprehensive robust counterparts of uncertain problems."

Friday, February 9, 2018 3:30 PM EST

**Title:** Post-Quantum Group-based Cryptography

Speaker: | Delaram Kahrobaei |

Affiliation: | New York University |

Room: | MC 5501 |

**Abstract:**

The National Security Agency (NSA) in August 2015 announced plans to transition to post-quantum algorithms

Thursday, February 8, 2018 3:30 PM EST

**Title:** An introduction to vertex minors

Speaker: | Jim Geelen |

Affiliation: | University of Waterloo |

Room: | MC 5479 |

**Abstract:**

This introductory lecture on vertex minors of graphs will highlight the similarities and differences with minors of graphs. We will also discuss the main conjectures relating to vertex minors.

Thursday, February 8, 2018 1:30 PM EST

**Title:** Constructing Graphs Pseudo-Similar Vertices

Speaker: | Cathy Wang |

Affiliation: | University of Waterloo |

Room: | MC 6486 |

**Abstract:**

Let G be a graph. Let a and b be vertices in G, then a and b are pseudo-similar if G\a is isomorphic to G\b, but there's no automorphism of G that maps a onto b.

Wednesday, February 7, 2018 4:00 PM EST

**Title:** Robust Convex Optimization

Speaker: | Nargiz Kalantarova |

Affiliation: | University of Waterloo |

Room: | MC 5479 |

**Abstract:**

We continue our study of convex optimization problems with uncertain data by discussing the paper by Ben-Tal and Nemirovski, 'Robust Convex Optimization'.

Tuesday, February 6, 2018 4:30 PM EST

**Title:** An Introduction to Quantum Graphs, Chromatic Numbers and Lovász Inequalties

Speaker: | Arthur Mehta |

Affiliation: | Pure Math - University of Waterloo |

Room: | MC 5501 |

**Abstract:**

Quantum graph theory, also known as non-commutative graph theory, is an operator system generalization of graph theory. Quantum graphs were first used to extend the notion of one-shot-zero-error capacity of a "Noisy Channel" to "Quantum Channels".

Monday, February 5, 2018 9:30 PM EST

**Title:** Algorithms and complexity for quantum advantage

Speaker: | David Gosset |

Affiliation: | IBM - T.J. Watson Research Center |

Room: | QNC 0101 |

**Abstract:**

There is strong evidence that a sufficiently large fault-tolerant quantum computer would solve certain computational problems exponentially faster than any classical computer. How can quantum algorithms and complexity theory help guide the way forward in our current era of small and noisy quantum computers?

Monday, February 5, 2018 1:00 PM EST

**Title:** ALBANIS: A brief overview of Lattice-Based NIST Submissions

Speaker: | Luis Ruiz |

Affiliation: | University of Waterloo |

Room: | MC 6486 |

**Abstract:**

Now that the NIST competition is in the first round of the review process, it is our turn to take a look at the submissions (at least, briefly).

Friday, February 2, 2018 9:30 AM EST

**Title:** Polynomial systems: Graphical structure, Geometry, and Applications

Speaker: | Diego Cifuentes |

Affiliation: | MIT |

Room: | MC 5501 |

**Abstract:**

Various problems in areas such as robotics, power systems, computer vision, cryptography, and chemical reaction networks, can be modeled by systems of polynomial equations, and in many cases the resulting systems have a simple sparsity structure.

Thursday, February 1, 2018 1:30 PM EST

**Title:** On Pretty Good State Transfer, Entanglement, and Spin Chains

Speaker: | Christopher van Bommel |

Affiliation: | University of Waterloo |

Room: | MC 6486 |

**Abstract:**

We discuss the Vieira and Rigolin paper “Almost perfect transport of an entangled two-qubit state through a spin chain”,

Combinatorics & Optimization

University of Waterloo

Waterloo, Ontario

Canada N2L 3G1

Phone: 519-888-4567, ext 33038

PDF files require Adobe Acrobat Reader.

University of Waterloo

University of Waterloo

43.471468

-80.544205

200 University Avenue West

Waterloo,
ON,
Canada
N2L 3G1

The University of Waterloo acknowledges that much of our work takes place on the traditional territory of the Neutral, Anishinaabeg and Haudenosaunee peoples. Our main campus is situated on the Haldimand Tract, the land granted to the Six Nations that includes six miles on each side of the Grand River. Our active work toward reconciliation takes place across our campuses through research, learning, teaching, and community building, and is co-ordinated within the Office of Indigenous Relations.