Contact Info
Combinatorics & Optimization
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 519-888-4567, ext 33038
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Friday, September 28, 2018 — 3:30 PM EDT
Title: The Shapiro-Shapiro Conjecture
| Speaker: | Kevin Purbhoo |
| Affiliation: | University of Waterloo |
| Room: | MC 5501 |
Abstract:
Given four lines in 3-space, can you find a fifth line that intersects the other four? How many?
This is the smallest non-trivial example of a "Schubert problem". The answer, in this case, is not hard to compute: there are two such lines. Generalizations of this fact date back to 19th century work of Schubert.
Thursday, September 27, 2018 — 3:30 PM EDT
Title: A characterization of (p,q)-mixing when p/q < 4
| Speaker: | Ben Moore |
| Affiliation: | University of Waterloo |
| Room: | MC 5417 |
Abstract: Let Hom(G,H) be the graph whose vertex set is the set of H-colourings of G, and two H-colourings f and g are adjacent if f differs from g in at most one vertex.
Thursday, September 20, 2018 — 3:30 PM EDT
Title: Naji’s characterization of circle graphs
| Speaker: | Jim Geelen |
| Affiliation: | University of Waterloo |
| Room: | MC 5417 |
Abstract: A circle graph is the intersection graph of chords of a circle.
Friday, September 14, 2018 — 3:30 PM EDT
Title: Rapid mixing of Glauber dynamics for colorings below Vigoda’s 11/6 threshold
| Speaker: | Michelle Delcourt |
| Affiliation: | University of Waterloo |
| Room: | MC 5501 |
Abstract:
A well-known conjecture in computer science and statistical physics is that Glauber dynamics on the set of k-colorings of a graph G on n vertices with maximum degree Δ is rapidly mixing for k ≥ Δ+2.
Friday, September 14, 2018 — 11:30 AM EDT
Title: Science of Security-- Could Such a Thing Exist?
| Speaker: | Paul van Oorschot |
| Affiliation: | Carelton University |
| Room: | MC 5501 |
Abstract: Recent years have seen increasing calls to make security research more "scientific". Who can argue with science being desirable?
Thursday, September 13, 2018 — 3:30 PM EDT
Title: Entropy and enumeration
| Speaker: | Jorn van der Pol |
| Affiliation: | University of Waterloo |
| Room: | MC 5417 |
Abstract: The information-theoretic concept of entropy is closely related to enumeration;
Friday, September 7, 2018 — 3:30 PM EDT
Title: The smallest eigenvalues of Hamming, Johnson and other graphs
| Speaker: | Sebastian Cioaba |
| Affiliation: | University of Delaware |
| Room: | MC 5501 |
Abstract:
The smallest eigenvalue of graphs is closely related to other graph parameters such as the independence number, the chromatic number or the max-cut.