Centre for Mathematics, University of Coimbra

Seminars

Contact sub-Riemannian structures as non-transitive Cartan geometries

2026-04-22

Speaker: João Nuno Mestre (CMUC)

Cartan geometries are structures on manifolds which are infinitesimally modelled on homogeneous spaces. For example, Riemannian structures are infinitesimally modelled by the euclidean space. The classical theory deals with "transitive" Cartan geometries, where the infinitesimal model is the...

Transport estimates between heat equation and the Goldstein-Kac telegraph equation

2026-04-24

Speaker: Gerardo Barrera (IST, Lisboa)

In this presentation we will obtain a non-asymptotic process level control between the telegraph process (a.k.a. Goldstein--Kac equation/process) and a Brownian motion with explicit diffusivity constant via a transportation Wasserstein path-distance with quadratic average cost. We stress...

On the protomodular and Mal'tsev properties for varieties of ordered algebras

2026-04-28

Speaker: Diana Rodelo (Univ. do Algarve)

The aim of the talk is to study the notions of lax protomodular category [1] and \( \mathsf{Ord} \)-Mal'tsev category [2] in the context of (coherent) varieties of (pre)ordered algebras and to compare them, as has been done in the non-ordered context. We characterise varieties of ordered...

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2026-04-28

Speaker: Manuel Kahala Ostrogadsky (Univ. Agostinho Neto, Angola)

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Deformations of Lie algebroid morphisms and geometric structures

2026-04-29

Speaker: Sebastián Daza (CMUC, UC|UP PhD student)

In this talk we will see how to associate to a geometric structure a Lie algebroid morphism. Moreover, we will study deformations of Lie algebroid morphisms and define a deformation complex controlling such deformations. To conclude, we will apply this abstract formalism to study...

Unitriangular groups, pattern subgroups, and hypertopes

2026-04-29

Speaker: João Dias (Univ. de Évora)

We introduce pattern geometries, a new class of coset geometries constructed from pattern groups inside unitriangular groups \( U_n(q) \). Using a coset geometry framework, we define these geometries via families of maximal parabolic subgroups derived from the covering relations of an...

Nerves of T-categories and powerful T-functors

2026-05-04

Speaker: Soichiro Fujii (Kyoto Univ., Japan)

Burroni's \( T \)-categories generalize internal categories, which themselves generalize ordinary (small) categories. The classical nerve construction assigns to a small category a simplicial set, and this construction extends routinely to internal categories: any internal category in a...

Coinductive reasoning for parametrized functors and monads

2026-05-04

Speaker: Zeinab Galal (Kyoto Univ., Japan

Lax extensions (also called relators or relation liftings) are a categorical notion for reasoning about functors acting on functions and relations in a compatible way. They play a central role in developing sound proof principles for behavioral equivalence of state-based systems and are also...

Can a non-trivial isometric quotient of the unit n-sphere be made arbitrarily small?

2026-05-07

Speaker: Claudio Gorodski (Univ. São Paulo, Brazil)

We will explain our proof of the existence of \( \varepsilon >0 \) such that every quotient of the unit sphere \( S^n (n\geq 2) \) by a isometric group action has diameter zero or at least \( \varepsilon \). The novelty is the independence of \( \varepsilon \) from \( n \). The...

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2026-05-12

Speaker: Juan Gabriel Calvo (Univ. of Costa Rica, Costa Rica)

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2026-06-16

Speaker: Rafael Díaz Fuentes (Università di Cagliari, Italy)

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2026-06-19

Speaker: Irene Fonseca (Carnegie Mellon University, USA)

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Using symplectic groupoid multiplication for Poisson integrators

2026-06-24

Speaker: Alejandro Cabrera (Uni. Politècnica de Catalunya, Spain)

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2026-10-22

Speaker: Thomas Kriecherbauer (Univ. of Bayreuth, Germany)

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