AARMS COVID-19 Seminar: Tom Hurd (McMaster)
2021-05-31 15:00 - 16:30 (America/Halifax) | Zoom seminar
From Agent Based Infectious Disease Models to Compartment Models
There are lots of potential agent based approaches to COVID modelling, and it is of interest to try to connect them to more standard compartment ODE models. To what extent can any ODE model capture the properties of a given ABM? The Inhomogeneous Random Social Network (IRSN) framework I have developed recently provides an explicit setting where such questions can be explored mathematically. The IRSN approach starts with a finite number N of heterogeneous agents that interact according to AB type rules. Under some conditions, one can analyze their large N limit, and under even more conditions, derive a limiting standard stratified compartment ODE model. The IRSN framework can be made arbitrarily fine-grained in many dimensions, including demographic classification, immunology (multiple variants), contact settings (types of contact locations) but only certain combinations of features are relevant to the ODE limit. ABMs capture characteristics such as non-homogeneous mixing that are not easily captured in any ODE model, so they help to understand the impact of such characteristics on disease propagation.
IRSN Model Paper: https://www.sciencedirect.com/science/article/pii/S2468042720300713
More information about this seminar series. This is a virtual zoom seminar. If you would like to attend, please email the organizers for connection details. All times are given in the Atlantic timezone.

Blundon Seminar Math Camp
2021-05-19 - 2021-05-21 | Memorial University (St. John’s Campus), St. John's, Newfoundland and Labrador, Canada
The Blundon Seminar is an annual (since 1982) three-day math
camp for senior high school students from Newfoundland who are
interested in mathematics and demonstrate consistently good
performance in mathematics competitions. Participation in the math
camp is by invitation only based on the results of preceding Blundon,
COMC, Euclid, Fermat, and Cayley contests. During the seminar the
students attend two one-hour talks given by professors from MUN on
various mathematical topics and applications in science and
engineering. There are several problem solving sessions as well as
other activities such as Mathletics and Papers Chase. The winner of
Blundon Contest is presented with the Blundon Shield, and the
winners of other contests are also presented with money and book
prizes. The awards for the best results in mathematics competitions
are presented during the banquet, where a collective photo is taken
as well.

AARMS COVID-19 Seminar: Madeleine Gorman-Asal (University of New Brunswick Fredericton)
2021-05-17 15:00 - 16:30 (America/Halifax) | Zoom seminar
Using a Mathematical Model to Investigate the Efficacy of Asymptomatic Testing to Detect SARS-CoV-2
A mathematical model was constructed to investigate the efficacy of asymptomatic testing for SARS-CoV-2 detection. Preliminary data suggests that the stage of disease at the time of testing impacts its efficacy. The probability of being detected by the asymptomatic test was compared by the number of days waited until taking the test since arrival given the unknown state of disease at arrival, the variability of the infectious period and whether case detection efforts were undergone prior to arrival. It was found that if assuming an equal probability of being in the incubation stage or an asymptomatic infectious stage, waiting until the fifth day since arrival to be tested is the earliest testing date that results in more detected than undetected cases. Additionally, in the 50% of COVID-19 cases with an infectious period longer than 22 days, there are limited differences in the probability of being detected when tested within the first 2, 5 or 8 days since arrival.
This is a virtual zoom seminar. If you would like to attend, please email the organizers for connection details. All times are given in the Atlantic timezone.

Canadian Student and Postdoc Conference on Gravity
2021-05-04 - 2021-05-06 | Online via Zoom
The Canadian Student and Postdoc Conference on Gravity (CSPCG) will provide a forum for both Canadian and international graduate students and postdocs to gather and present their research. It invites submissions for talks covering all aspects of gravitational research, including mathematical and numerical relativity, quantum gravity, string-theoretic approaches to gravity, gravitational waves, relativistic astrophysics, and cosmology. It will run as a virtual event from May 4-6, 2021, creating an accessible platform for students and postdocs who do not necessarily have the financial resources or ability to travel. The CSPCG is committed to diversity and inclusivity; and welcomes all participants, including women; people of any sexual orientation, gender identity, or gender expression; Indigenous peoples; visible minorities/racialized people; and people with disabilities.

Groups acting on Trees: minicourse by Olga Kharlampovich
2021-05-03 - 2021-05-07 | Online via Zoom
From May 3, 2021 to May 7, 2021, Professor O. Kharlampovich from City University of New York will teach a mini course on Groups acting on Trees. Due to the current situation caused by the corona virus disease, the mini course will take place virtually.
Bass-Serre theory relates group actions on trees with decomposing groups as iterated applications of the operations of amalgamated product and HNN extension, via the notion of the fundamental group of a graph of groups.
One of the generalizations of Bass-Serre theory is the theory of isometric group actions on real trees (R-trees) which are metric spaces generalizing the graph-theoretic notion of a tree. Group actions on R-trees arise naturally in geometric topology, as well as in geometric group theory. Asymptotic cones of groups often have a tree-like structure and give rise to group actions on real trees. The use of R-trees and $Lambda$ -trees, in particular Zn-trees, together with Bass-Serre theory, are key tools in the work on the elementary theory of a free group by Kharlampovich-Miasnikov and Sela.
The course will be suitable for undergraduates, graduate students, postdocs, faculty, and anyone interested in algebra. The internet address for the virtual meeting room will be available at https://www.mun.ca/aac/AACMiniCourses/olga/
The mini course will take place from 10 to 10:50 Eastern Standard Time.

AARMS COVID-19 Seminar: Ahmed Saif (Dalhousie)
2021-04-21 10:30 - 11:30 (America/Halifax) | Zoom seminar
A Simulation-Optimization Framework for Optimizing Response Strategies to Epidemics
Epidemics require dynamic response strategies that encompass a multitude of policy alternatives and that balance health, economic and societal considerations. We propose a simulation-optimization framework to aid policymakers select closure, protection and travel policies to minimize the total number of infections under a limited budget. The proposed framework combines a modified, age-stratified SEIR compartmental model to evaluate the health impact of response strategies and a Genetic Algorithm to effectively search for better strategies. We implemented our framework on a real case study in Nova Scotia to devise optimized response strategies to COVID-19 under different budget scenarios and found a clear trade-off between health and economic considerations. Closure policies seem to be the most sensitive to budget restrictions, followed by travel policies. On the other hand, results suggest that practicing social distancing and wearing masks are necessary under all scenarios. The framework is generic and can be extended to encompass vaccination policies and to use different epidemiological models and optimization methods.
Ahmed Saif, Ph.D., P.Eng., is an Assistant Professor in the Department of Industrial Engineering at Dalhousie University. He received a Ph.D. in Management Sciences from the University of Waterloo, an M.Sc. in Engineering Systems and Management from Masdar Institute of Science and Technology, an MBA from New York Institute of Technology and a B.Sc. in Production Engineering from Alexandria University. Prior to joining Dalhousie University, he spent a year as a Postdoctoral Fellow in HEC Montréal. He also has several years of experience in engineering and consulting companies in Canada and abroad. Dr. Saif’s research focuses on large-scale optimization, decision making under uncertainty and data analytics methods and their applications in hybrid renewable energy systems and sustainable supply chain problems. His research has been funded by various agencies including NSERC and MITACS, and has been published in high-impact journals, including INFORMS Journal on Computing, Computer & Operations Research
This is a virtual zoom seminar. If you would like to attend, please email the organizers for connection details. All times are given in the Atlantic timezone.

Dalhousie-AARMS AAMP Seminar: Chunyi Gai (Dalhousie University)
2021-04-09 16:00 - 17:00 (America/Halifax) | Zoom seminar
The Dalhousie-AARMS Analysis-Applied Math-Physics Seminar takes place on Fridays from 4 – 5 pm Atlantic Time over Zoom. If you would like to attend, please email the organizers for connection details.

Atlantic Graph Theory Seminar: Dr Jason Brown & Dr Corey DeGagne, Dalhousie University
2021-04-07 15:30 - 16:30 UTC | Zoom seminar
The Atlantic Graph Theory Seminar series will take place every Wednesday from 3:30-4:30 ADT online via zoom. The talks, provided by researchers, postdocs and graduate students, will be on a variety of current topics in graph theory. If you would like to give a talk or attend, please email one of the organizers (Jason Brown and Danielle Cox).

Atlantic GR Seminar: Dr Robie Hennigar (MUN)
2021-03-31 13:00 - 14:00 (America/Halifax) | Zoom seminar
Holographic Complexity and Thermodynamic Volume
I will discuss recent work exploring the holographic complexity conjectures for rotating black holes. A relationship between the complexity of formation and the thermodynamic volume of the black hole is found, and I discuss the evidence that suggests this relationship holds generally. This is one of the first connections between thermodynamic volume and holography, and I will discuss possible implications.
The Atlantic General Relativity 2020 online postdoc/student seminar series is in the tradition of the annual AGR meetings, providing a forum not only for students and postdocs to present their research and make professional contacts but also to facilitate connections and collaborations between all Atlantic Canadian relativists. The series is student-organized and includes all areas of classical and quantum gravity. Talks will occur on the last Wednesday of every month, with each session consisting of two 30 minute talks. If you would like to attend, please email the organizers for connection details.
Note: all times are Atlantic Time

Dalhousie-AARMS AAMP Seminar: Jared Wunsch (Northwestern University)
2021-03-26 16:00 - 17:00 (America/Halifax) | Zoom seminar

Atlantic Graph Theory Seminar: Dr Danielle Cox, Mount Saint Vincent University
2021-03-24 15:30 - 16:30 UTC | Zoom seminar

Dalhousie-AARMS AAMP Seminar: Marco Merkli (MUN)
2021-03-19 16:00 - 17:00 (America/Halifax) | Zoom seminar

Atlantic Graph Theory Seminar: Dr Peter Danziger, Ryerson University
2021-03-17 15:30 - 16:30 UTC | Zoom seminar

AARMS COVID-19 Seminar: Ting-Hao Hsu (UNB)
2021-03-17 10:30 - 11:30 (America/Halifax) | Zoom seminar
Slow-Fast Systems in Epidemic Models
Differential equations involving slow and fast time scales have been adopted in mathematical modelling to capture rapid changes occurred in the epidemic systems. Examples include outbreaks of infectious diseases and autonomous behavioural changes of individuals. I will introduce a new technic in slow-fast systems to analyze relaxation oscillations, i.e., periodic orbits with slow and fast segments, in such models. The approach is based on extending the so-called entry-exit function to multi-dimensional slow-fast systems using the geometric singular perturbation theory.
This is a virtual zoom seminar. If you would like to attend, please email the organizers for connection details. All times are given in the Atlantic timezone.

Dalhousie-AARMS AAMP Seminar: François Monard (U. California, Santa Cruz)
2021-03-12 16:00 - 17:00 (America/Halifax) | Zoom seminar

Atlantic Graph Theory Seminar: Dr Nancy Clarke, Acadia University
2021-03-10 15:30 - 16:30 UTC | Zoom seminar

Dalhousie-AARMS AAMP Seminar: Steven Lester (King's College London)
2021-03-05 16:00 - 17:00 (America/Halifax) | Zoom seminar

Atlantic Graph Theory Seminar: Dr Jeannette Janssen, Dalhousie University
2021-03-03 15:30 - 16:30 UTC | Zoom seminar

AARMS COVID-19 Seminar: James Watmough (UNB)
2021-03-03 10:30 - 11:30 (America/Halifax) | Zoom seminar
Case importation and community spread: post-pandemic control of the spread of SARS-CoV-2 in low density populations
It has been just over one year and 100 million cases since we first heard of a novel coronavirus with pandemic potential. We are now all far too familiar with epidemic curves and would very much like to see the tail of this one. In this talk, I will review the simple mathematical models for the transition from pandemic to endemic and what they tell us about this tail.
For the past year, Canada has kept case numbers relatively low through a combination of community quarantine and travel restrictions. In theory, this has implications for how we approach and manage the new normal of endemic SARS-CoV-2. I will focus on what this might mean for Atlantic Canada.
This is a virtual zoom seminar. If you would like to attend, please email the organizers for connection details. All times are given in the Atlantic timezone.

Atlantic Graph Theory Seminar: Dr. Gary Gordon, Lafayette College
2021-02-24 15:30 - 16:30 UTC | Zoom seminar
Permutations of finite subsets of R^2 generated by Euclidean distances
Given a finite set of points S = {P1, P2, . . . , Pn} and a vantage point V, generate an ordering of the points of S by measuring the Euclidean distance from V to each of the points of S, ordering them from nearest to farthest. As the vantage point moves around the plane, different orderings will be generated. We are interested in the maximum, minimum, and intermediate values achievable for different point-sets S. (Good and Tideman solved the maximum problem in all dimensions in the 1970s.) We also consider a generalization that uses two vantage points, using the average distance (d(V1, Pk) + d(V2, Pk))/2 to the points of S to generate an ordering.
The Atlantic Graph Theory Seminar series will take place every Wednesday from 3:30-4:30 ADT online via zoom. The talks, provided by researchers, postdocs and graduate students, will be on a variety of current topics in graph theory. If you would like to give a talk or attend, please email one of the organizers (Jason Brown and Danielle Cox).

Atlantic GR Seminar: Sarah Muth (MUN)
2021-02-24 13:00 - 14:00 (America/Halifax) | Zoom seminar
Marginally Outer Trapped (Open) Surfaces in 4+1 Dimensional Schwarzschild
In the case of binary black hole mergers, the surface of most obvious interest, the Event Horizon, is often computationally difficult to locate. Instead, it is useful to turn to quasi-local characterizations of black hole boundaries, such as Marginally Outer Trapped Surfaces (MOTS), which are defined for a single time slice of the spacetime, and the outer-most of which is the apparent horizon. In this talk, I will describe ongoing work focused on understanding MOTS in the interior of a five-dimensional Schwarzschild black hole. Similar to the four-dimensional case previously studied, we find examples of self-intersecting MOTS with an arbitrary number of self-intersections. This provides further support that self-intersecting behavior is rather generic. I will also briefly discuss the next stage of our research, which involves further examples of these self-intersecting MOTS, this time in the full Kruskal extension of Schwarzschild.
The Atlantic General Relativity 2020 online postdoc/student seminar series is in the tradition of the annual AGR meetings, providing a forum not only for students and postdocs to present their research and make professional contacts but also to facilitate connections and collaborations between all Atlantic Canadian relativists. The series is student-organized and includes all areas of classical and quantum gravity. Talks will occur on the last Wednesday of every month, with each session consisting of two 30 minute talks. If you would like to attend, please email the organizers for connection details.
Note: all times are Atlantic Time

AARMS COVID-19 Seminar: JC Loredo-Osti (Memorial)
2021-02-17 10:30 - 11:30 (America/Halifax) | Zoom seminar
Covid-19 management in Newfoundland and Labrador
Atlantic Canada and the territories have experienced a qualitatively different COVID-19 epidemic than the other Canadian provinces. The question is, do these differences suggest different best approaches to public health policy or they are just the consequence of geographic/demographic conditions? When infection prevalence is low, imported infections are not only a large fraction of all infections, but a major trigger of outbreaks. This also posses questions about the merits of travel restrictions as well as the escalation of measures in response to outbreaks. On this presentation, we will discuss some of the ways to quantify these issues in the context of the pandemic in Atlantic Canada, and in particular in Newfoundland and Labrador.
This is a virtual zoom seminar. If you would like to attend, please email the organizers for connection details. All times are given in the Atlantic timezone.

Atlantic Graph Theory Seminar: Dr Anthony Bonato, Ryerson University
2021-02-10 15:30 - 16:30 UTC | Zoom seminar
The localization game played on graph
Graph searching investigates combinatorial models for the detection or neutralization of an adversary’s activity on a network. One such model is the localization game, where pursuers use distance probes to capture an invisible evader. We present new results on the localization number of a graph, which is the minimum number of pursuers needed to capture the evader. We survey what is known and unknown for the localization number, discuss connections with the chromatic number, and give bounds on graph families such as hypercubes, incidence graphs of combinatorial designs, and Kneser graphs.
The Atlantic Graph Theory Seminar series will take place every Wednesday from 3:30-4:30 ADT online via zoom. The talks, provided by researchers, postdocs and graduate students, will be on a variety of current topics in graph theory. If you would like to give a talk or attend, please email one of the organizers (Jason Brown and Danielle Cox).

AARMS COVID-19 Seminar: Sanjeev Seahra (UNB)
2021-02-03 10:30 - 11:30 (America/Halifax) | Zoom seminar
COVID-19 modelling in New Brunswick and elsewhere
We present a simple differential equation based model of the COVID-19 pandemic that allows for time-evolving social distancing. We apply the model to the first 80 days of the pandemic in 24 different jurisdictions to quantify the effectiveness of government lockdowns in March 2020. Using Bayesian methods, we then estimate model parameters relevant to the current outbreak in New Brunswick.
This is a virtual zoom seminar. If you would like to attend, please email the organizers for connection details. All times are given in the Atlantic timezone.

Dalhousie-AARMS AAMP Seminar: Alan Lindsay (Notre Dame)
2021-01-29 16:00 - 17:00 (America/Halifax) | Zoom seminar

Atlantic Graph Theory Seminar: Jordan Barrett, PhD Candidate, McGill University
2021-01-27 15:30 - 16:30 UTC | Zoom seminar

Dalhousie-AARMS AAMP Seminar: Allan Greenleaf (Rochester)
2021-01-22 16:00 - 17:00 (America/Halifax) | Zoom seminar

Atlantic Graph Theory Seminar: Dr. Hugh Thomas, UQAM
2021-01-20 15:30 - 16:30 UTC | Zoom seminar
Dynamical algebraic combinatorics and independence sets of graphs
Dynamical algebraic combinatorics is a relatively new (and fun!) topic, which looks at cyclic group actions on objects from algebraic combinatorics, inspired by some questions coming from dynamical systems. I will give an introduction to the area, focusing on an action I have defined with Nathan Williams on the independent sets of a graph (arXiv:1805.00815). We also construct a partial order on the set of independent sets of a graph, which may be of independent interest.
The Atlantic Graph Theory Seminar series will take place every Wednesday from 3:30-4:30 ADT online via zoom. The talks, provided by researchers, postdocs and graduate students, will be on a variety of current topics in graph theory. If you would like to give a talk or attend, please email one of the organizers (Jason Brown and Danielle Cox).

Atlantic Graph Theory Seminar: Dr Stephen Finbow, Saint Francis Xavier University
2021-01-13 15:30 - 16:30 UTC | Zoom seminar
The γ-graph of a graph
For a graph G = (V, E), the γ-graph of G, G(γ) = (V (γ), E(γ)), is the reconfiguration graph whose vertex set is the collection of minimum dominating sets, or γ-sets of G, and two γ-sets are adjacent in G(γ) if they differ by a single vertex and the two different vertices are adjacent in G. The γ-graph of G was introduced by Fricke et al. in 2011 where they studied properties of γ-graphs, and raised seven questions. In this seminar we will discuss the study of γ-graphs to date with a focus on the progress of these questions.
The Atlantic Graph Theory Seminar series will take place every Wednesday from 3:30-4:30 ADT online via zoom. The talks, provided by researchers, postdocs and graduate students, will be on a variety of current topics in graph theory. If you would like to give a talk or attend, please email one of the organizers (Jason Brown and Danielle Cox).

AARMS COVID-19 Seminar: Ali Gharouni (McMaster)
2020-12-16 15:00 - 16:30 (America/Halifax) | Zoom seminar
COVID-19 Outbreak Dynamics and Testing-Isolation Efficacy; Insights from a Simple Epidemic Model
One of the main challenges in understanding COVID-19 dynamics is to estimate changes in the total level of infection in a population. The daily case count is a highly accessible form of data where observations are driven by two types of processes: (i) epidemic processes and (ii) testing processes. The challenge is then to separate these processes and understand how they interact. We developed a model that incorporates mechanistic processes of epidemic processes and testing. We have used the model to study the potential
effect of testing strategies on disease dynamics. In future work, we will develop improved methods for estimating true incidence by using data from negative as well as positive tests.
In collaboration with: Fady Abdelmalek and Drs Benjamin M Bolker, Jonathan Dushoff, David JD Earn
This is a virtual zoom seminar. If you would like to attend, please email the organizers for connection details. All times are given in the Atlantic timezone.
