Department of Mathematics

PIMS at SFU

Events and Deadlines

 

 

 

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  • 3
    Thu
  • 7
    Mon
    • 10:00 pm – 11:00 pm (UTC)
      APR 7 / SFU MATHEMATICS OF COMPUTATION, APPLICATION AND DATA SEMINAR / ELENA CELLEDONI / NTNU

      APR 7 / SFU MATHEMATICS OF COMPUTATION, APPLICATION AND DATA SEMINAR / ELENA CELLEDONI / NTNU

      Monday, April 7, 10:00 pm – 11:00 pm (UTC)
      Speaker
      Elena Celledoni
      Affiliation
      NTNU
      Location
      K9509 and Hybrid
      Title
      Shape analysis, structure preservation and deep learning
      Shape analysis is a framework for treating complex data and obtain metrics on spaces of data. Examples are spaces of unparametrized curves, time-signals, surfaces and images. In this talk we discuss structure preservation and deep learning for classifying, analysing and manipulating shapes. A computationally demanding task for estimating distances between shapes, e.g. in object recognition, is the computation of optimal reparametrizations. This is an optimisation problem on the infinite dimensional group of orientation preserving diffeomorphisms. We approximate diffeomorphisms with neural networks and use the optimal control and dynamical systems point of view to deep learning. We will discuss useful geometric properties in this context e.g. reparametrization invariance of the distance function and inherent geometric structure of the data. Another interesting set of related problems arises when learning dynamical systems from (human motion) data.
      More Info
  • 10
    Thu
    • 8:30 pm – 9:30 pm (UTC)
      APR 10 / SFU NUMBER THEORY AND ALGEBRAIC GEOMETRY SEMINAR / KATRINA HONIGS / SFU

      APR 10 / SFU NUMBER THEORY AND ALGEBRAIC GEOMETRY SEMINAR / KATRINA HONIGS / SFU

      Thursday, April 10, 8:30 pm – 9:30 pm (UTC)
      Title
      McKay correspondence for reflection groups and derived categories
      Location
      SFU K9509
      Speaker
      Katrina Honigs
      Affiliation
      SFU
      The classical McKay correspondence shows that there is a bijection between irreducible representations of finite subgroups $G$ of $\mathrm{SL}(2,\mathbb{C})$ and the exceptional divisors of the minimal resolution of the singularity $\mathbb{C}^2/G$. This is a very elegant correspondence, but it's not at all obvious how to extend these ideas to other finite groups. Kapranov and Vasserot, and then, later, Bridgeland, King and Reid showed this correspondence can be recast and extended as an equivalence of derived categories of coherent sheaves. When this framework is extended to finite subgroups of $\mathrm{GL}(2,\mathbb{C})$ generated by reflections, the equivalence of categories becomes a semiorthogonal decomposition whose components are, conjecturally, in bijection with irreducible representations of $G$. This correspondence has been verified in recent work of Potter and of Capellan for a particular embedding of the dihedral groups $D_n$ in $\mathrm{GL}(2,\mathbb{C})$. I will discuss recent joint work verifying this decomposition in further cases.
      More Info
    • 9:00 pm – 10:00 pm (UTC)
      APR 10 / PIMS-CORDS SFU OPERATIONS RESEARCH SEMINAR / KRISZTINA VASARHELYI / VANCOUVER COASTAL HEALTH

      APR 10 / PIMS-CORDS SFU OPERATIONS RESEARCH SEMINAR / KRISZTINA VASARHELYI / VANCOUVER COASTAL HEALTH

      Thursday, April 10, 9:00 pm – 10:00 pm (UTC)
      Title
      TBA
      Speaker
      Krisztina Vasarhelyi
      Affiliation
      Vancouver Coastal Health
      Location
      Remote
      Coming Soon!!
      More Info
  • 11
    Fri
  • 15
    Tue
    • All Day (UTC)
      APR 15 / PROPOSALS DEADLINE / PIMS/BIRS TEAM UP! / PATHWAYS TO INCLUSIVE RESEARCH

      APR 15 / PROPOSALS DEADLINE / PIMS/BIRS TEAM UP! / PATHWAYS TO INCLUSIVE RESEARCH

      Tuesday, April 15, All Day (UTC)
      Sites
      BIRS Banff or Kelowna Site
      Deadline
      April 15, 2025
      The PIMS/BIRS Team Up! program provides opportunities for in-person collaboration to teams of mathematical scientists, targeting researchers whose research program may have been disproportionately affected by various obstacles like family obligations, professional isolation, access to funding, and the COVID-19 pandemic. This includes, but need not be limited to, women, gender-expansive, and minoritized groups, Indigenous scholars, individuals with visible/invisible challenges and early-career researchers with limited resources. Successful applicants will receive lodging and meals (subject to availability) at either the Banff or Kelowna BIRS site, as well as reasonable reimbursement for travel expenses. A key goal of this program is for researchers with caregiving responsibilities to participate fully in its scientific activities. To this end, support may also be offered in the form of lodging and reimbursement of travel expenses for children accompanying the member, as well as lodging and travel expenses for a caregiver.
      More Info
  • 16
    Wed
    • 10:00 pm – 11:00 pm (UTC)
      APR 16 / SFU MATHEMATICS OF COMPUTATION, APPLICATION AND DATA SEMINAR / BRYNJULF OWREN / NTNU

      APR 16 / SFU MATHEMATICS OF COMPUTATION, APPLICATION AND DATA SEMINAR / BRYNJULF OWREN / NTNU

      Wednesday, April 16, 10:00 pm – 11:00 pm (UTC)
      Speaker
      Brynjulf Owren
      Affiliation
      NTNU
      Location
      K9509 and Hybrid
      Title
      A dynamical systems approach for designing stable neural networks on Euclidean spaces and Riemannian manifolds
      Recently, Sherry et al. (2024) reconsidered the pioneering work of Dahlquist and Jeltsch (1979) on circle-contractivity for the study of neural networks. This theory can be used to analyse and improve the robustness of architectures that are devised by a dynamical systems approach. The main idea is to start with a continuous dynamical system which satisfies a certain monotonicity condition. Then we need to discretize the system in a way that preserves the non-expansive behavior of the associated flow. The theory is old, but not necessarily widely known because Dahlquist and Jeltsch only published the results in the form of a preprint. The application to neural networks is new as far as we know, and we shall present some results and examples from Sherry et al (2024). The importance of neural networks set on Riemannian manifolds seems to be increasing and there is a need to develop the theory of non-expansive numerical methods also in such a setting. We present some ideas from Arnold et al. (2024) where a few simple numerical methods for Riemannian manifolds are studied. We consider whether these methods can be non-expansive when applied to non-expansive vector fields. For the geodesic implicit Euler method, which also feature in the proximal gradient method for optimisation, we find that its behaviour is strongly dependent on the sectional curvature of the manifold. As opposed to the Euclidean case, we now also have to be careful about whether the nonlinear equations to be solved in each time step has a unique solution or not.
      More Info
  • 24
    Thu
  • 26
    Sat
    • All Day (UTC)
      APR 26-27 / WESTERN ALGEBRAIC GEOMETRY SYMPOSIUM - SPRING 2025 / UBC

      APR 26-27 / WESTERN ALGEBRAIC GEOMETRY SYMPOSIUM - SPRING 2025 / UBC

      Saturday, April 26, All Day (UTC)
      The Western Algebraic Geometry Symposium (WAGS) is a twice-yearly meeting of algebraic geometers in the western part of North America. WAGS aims to build a regional community among algebraic geometers of all career stages, from advanced undergraduates to full professors. The meetings are centered around research talks delivered by leading mathematicians from around the world highlighting exciting recent results in and around algebraic geometry. In addition to the research talks, the typical WAGS also includes poster sessions and/or other organized opportunities for interaction among participants.
      More Info
  • 1
    Thu
    • All Day (UTC)
      MAY 1 / PROPOSALS DEADLINE / PIMS NETWORK WIDE GRADUATE COURSES 2025-2026

      MAY 1 / PROPOSALS DEADLINE / PIMS NETWORK WIDE GRADUATE COURSES 2025-2026

      Thursday, May 1, All Day (UTC)
      Deadline
      May 1, 2025
      The Pacific Institute for the Mathematical Sciences would like to hear from instructors willing to share their courses with participants at other PIMS universities. We invite proposals for graduate level courses in the mathematical sciences to take place in either term of the 2025-2026 academic year. Students taking these courses may be eligible for credit under the terms of the Western Deans Agreement (though conditions apply). Instructors participating in this program will benefit by reaching a larger potential audience, and from interactions with fellow instructors and PIMS staff on how to best develop network-wide offerings. These courses will be designated as PIMS network-wide graduate courses, and will be advertised and promoted throughout the PIMS network. If you are interested in participating as an instructor, please complete the instructor application form by May 1, 2025.
      More Info

APR 11 / SFU MATHEMATICS OF COMPUTATION, APPLICATION AND DATA SEMINAR / JAY GOPALAKRISHNAN / PORTLAND STATE

Friday, April 11, 10:00 pm – 11:00 pm (UTC)
Speaker
Jay Gopalakrishnan
Affiliation
Portland State University
Location
SFU West Mall 2830 and Hybrid
Title
TBA
Coming Soon!!
More Info
  More PIMS events: Please check out www.pims.math.ca for more events.  
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