Centre for Mathematics, University of Coimbra

Seminars

Normed categories

2025-05-20

Speaker: Walter Tholen (York Univ., Toronto, Canada)

In this talk we explore Lawvere's notion of normed category through the lens of easily understood small and large example categories. Cauchy convergence of sequences in such categories gets presented as a natural extension of familiar concepts taught in Calculus and Functional Analysis, but...

Self-dual aspects of semi-abelian categories

2025-05-20

Speaker: Tim Van der Linden (Univ. catholique de Louvain and Vrije Univ. Brussel, Belgium)

The aim of this talk is to introduce di-exact categories [3], which are defined by a simple axiom system capturing self-dual aspects of the context of Janelidze-Márki-Tholen semi-abelian categories [2,1]. A Borceux-Bourn homological category [1] is Barr-exact if and only if it is di-exact....

Fractal behavior of tensor powers of the two-dimensional space in prime characteristic

2025-05-22

Speaker: Pavel Etingof (MIT, Cambridge, USA)

TBA...

Polynomials whose roots are the differences of the roots of a given polynomial

2025-06-03

Speaker: Manuel A. Facas Vicente/José Vitória (DMUC, Univ. Coimbra)

TBA...

Quandles, cohomology and quivers

2025-06-04

Speaker: Sam Nelson (Claremont McKenna College, USA)

Knot theorists seek knot invariants, tools we can use to distinguish knots from each other and to probe their structure. In this talk I will introduce quandles, an algebraic category whose axioms encode the motion of knots through space analogously to how the group axioms encode geometric...

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2025-06-17

Speaker: Alfredo Costa (CMUC, Univ. Coimbra)

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2025-06-17

Speaker: Célia Borlido (CMUC, Univ. Coimbra)

TBA...

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2025-06-24

Speaker: Semyon Yakubovich (Univ. Porto)

TBA...

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2025-06-25

Speaker: Mateus Moreira de Melo (Univ. Fed. Espírito Santo, Brazil)

TBA...

Classifying cubic graphs avoiding spectral gap sets

2025-06-25

Speaker: Gordon Royle (Univ. Western Australia, Australia)

Spectral graph theory is the study of the relationship between the graphical properties of a graph and the spectral properties (i.e., eigenvalues and eigenvectors) of various matrices associated with that graph, most commonly the adjacency matrix. The spectrum of the...

Large random tilings of a hexagon

2025-09-15

Speaker: Arno Kuijlaars (KU Leuven, Belgium)

TBA...

Quasi-orthogonal polynomials and positive quadrature on the unit circle

2025-09-18

Speaker: Ruymán Cruz Barroso (University of La Laguna, Spain)

TBA...