Centre for Mathematics, University of Coimbra

Seminars

Non-commutative Number Theory and Diophantine equations

2025-07-09

Speaker: António Machiavelo (Univ. Porto)

We will report on new arithmetic results pertaining to orders in some particular quaternion algebras, and show how to use those results to solve Diophantine problems on the representation of integers by some quaternary quadratic forms. Some open problems will be described along the way....

Drazin inverses in (dagger) categories

2025-08-19

Speaker: Jean-Simon Pacaud Lemay (Macquarie Univ., Sydney, Australia)

Drazin inverses are a special kind of generalized inverse that have been extensively studied and have many applications in ring theory, semigroup theory, and matrix theory. Drazin inverses can also be defined for endomorphisms in any category. A natural question is whether one can extend the...

A general approach to pointfree \(T_0\) spaces

2025-08-19

Speaker: Anna Laura Suarez (Univ. Western Cape, South Africa)

The classical dual adjunction between frames and spaces, given by the functors \( O\colon \mathbf{Top}\to\mathbf{Frm} \) and \( \mathsf{pt}\colon\mathbf{Frm}\to\mathbf{Top} \), restricts to a dual equivalence between sober spaces and spatial frames. Another pointfree approach to the study of...

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...