Centre for Mathematics, University of Coimbra

Seminars

Delsarte's extremal problem and packing on locally compact Abelian groups

2024-05-21

Speaker: Elena Berdysheva (Univ. Cape Town, South Africa)

https://www.mat.uc.pt/~pgsfop/activities.html...

Structure of quasi-crystal graphs and applications to the combinatorics of quasi-symmetric functions

2024-05-29

Speaker: Inês Rodrigues (Univ. Nova de Lisboa)

Crystal graphs are powerful combinatorial tools for working with the plactic monoid and symmetric functions. Quasi-crystal graphs are an analogous concept for the hypoplactic monoid and quasi-symmetric functions.We explicitly describe a previously observed isomorphism of components of the...

Homomorphisms on holomorphic functions in infinite dimensions

2024-06-04

Speaker: Richard M. Aron (Kent State Univ., USA)

https://www.mat.uc.pt/~pgsfop/activities.html...

i-Fitting-Formations on Clifford semigroups

2024-06-04

Speaker: Ana Catarina Monteiro (CEMAT, Univ. Lisboa)

In this talk, we will explore the concept of i-Fitting-Formation of Clifford semigroups. A Clifford semigroup is an inverse semigroup that is a union of groups. A class of Clifford semigroups is an i-formation if it is closed for idempotent separating quotients and for finitary...

More than perfect but not perfect enough

2024-06-04

Speaker: Maria João Gouveia (CEMAT, Univ. Lisboa)

We start by presenting a brief overview of the various known lattice representations. From there we introduce some results of our work on TiRS graphs which abstract the lattice duals in Ploscica's representation (1995) via maximal partial maps into the two-element set. Those particular...

On chain polynomials of posets

2024-06-26

Speaker: Leonardo Saud Maia Leite (KTH Royal Institute of Technology, Sweden)

The chain polynomial of a finite lattice \( \mathcal{L} \) is given by \( p_\mathcal{L} (x) = \sum_{k \geq 0} c_k(\mathcal{L})x^k \), where \( c_k(\mathcal{L}) \) is the number of chains of length \( k \) in \( \mathcal{L} \). The chain polynomials of posets in several important classes have...

Gap labelling for periodic Jacobi matrices on trees

2024-09-24

Speaker: Barry Simon (Caltech, USA)

https://www.mat.uc.pt/~pgsfop/activities.html...