Seminários

Seminário de Geometria Algébrica e Geometria Complexa – 06/10/23 – Yerika Marín e Pablo Quezada Mora – online

Notícias, Seminários / Por

Caros colegas,

Seguem abaixo as informações dos nossos próximos dois Seminários de Geometria Algébrica e Geometria Complexa da UFF. 

Para consultar os próximos seminários e o histórico, basta consultar o site do Grupo de Geometria Algébrica e Complexa da UFF:

https://sites.google.com/view/geoalgcompluff

Palestrante: Yerika Marín

Título:  Generalized quasi-dihedral group acting on pseudo-real Riemann surfaces

Resumo: A closed Riemann surface of genus g \geq 2 is called pseudo-real if it has anticonformal automorphisms but no anticonformal involutions. These Riemann surfaces, together with real Riemann surfaces, form the real locus of the moduli space \mathcal{M}_g of closed Riemann surfaces of genus g \geq 2. On the other hand, pseudo-real Riemann surfaces are examples of Riemann surfaces which cannot be defined over their field of moduli [1]. In general, a finite group might not be realized as the group of conformal/anticonformal automorphisms, admitting anticonformal ones, of a pseudo-real Riemann surface, for instance, in [2], it was observed that a necessary condition for that to happen is for the group to have order a multiple of 4 . In this talk, we consider conformal/anticonformal actions of the generalized quasi-dihedral group of order 8 n,
G_n=\left\langle x, y: x^{4 n}=y^2=1, y x y=x^{2 n-1}\right\rangle \quad(\text { for } n \geq 2)
on pseudo-real Riemann surfaces. We consider two cases either G_n has anticonformal elements or G_n only contains conformal elements [3].
This is part of my Ph.D. Thesis, under the advisers Saúl Quispe and Rubén A. Hidalgo.

References
[1] M. Artebani, S. Quispe and C. Reyes. Automorphism groups of pseudoreal Riemann surfaces Journal of Pure and Applied Algebra 221 (2017), 2383-2407.
[2] E. Bujalance, M. D. E. Conder and A. F. Costa. Pseudo-real Riemann surfaces and chira regular maps, Trans. Am. Math. Soc. 362 (7) (2010), 3365-3376.
[3] R. A. Hidalgo, Y. Marín Montilla and S. Quispe. Generalized quasi-dihedral group as automorphism group of Riemann surfaces, Preprint 2022.

Data: 06/10/2023 (Sexta-feira)

Horário: 15h

Link: https://meet.google.com/mnw-coar-fji

Palestrante: Pablo Quezada Mora

Título: IHS Manifolds of K3^[2]-type with an action of Z_3^4 : A_6

Resumo:  In this talk we will study IHS manifolds of K3^[2]-type with a symplectic action of Z_3^4 : A_6, the symplectic group with the biggest order, and such that they also admit a non-symplectic automorphism. We will characterize the IHS manifolds that satisfies this, and particularly we will characterize the IHS manifold of K3^[2]-type with finite automorphism group of order 174960, the biggest possible order for the finite automorphism group of a IHS manifold of K3^[2]-type, and we will give an example of it. This is a joint work with Paola Comparin and Romain Demelle.

Data: 06/10/2023 (Sexta-feira)

Horário: 16h

Link: https://meet.google.com/mnw-coar-fji

Seminário de Geometria Algébrica e Geometria Complexa – 13/09/23 – Nivaldo Medeiros (UFF)

Notícias, Seminários / Por

Car@s colegas,

Segue abaixo as informações do próximo Seminário de Geometria Algébrica e Geometria Complexa da UFF. 

Para consultar os próximos seminários e o histórico, basta consultar o site do Grupo de Geometria Algébrica e Complexa da UFF:

https://sites.google.com/view/geoalgcompluff

Palestrante: Nivaldo Medeiros (UFF)

Título:Classes CSM e inversas de transformações de Cremona monomiais

Resumo: Dado um mapa birracional no espaço projetivo tridimensional definido por monômios de grau $d$, provamos que sua inversa é definida por monômios de grau no máximo $d^2-d+1$. Nossa abordagem consiste em reformular o problema em termos topológicos, via o uso de classes de Chern-Schwartz-MacPherson. 

Trabalho em colaboração com Thiago Fassarella (UFF)

Data: 13/09/2023 (Quarta-feira)

Horário: 16h

Sala: 407 – Bloco H – Gragoatá.

8° SIES (Seminário Interinstitucional de Estudantes de Sistemas Dinâmicos) – 28/08/23

Notícias, Seminários / Por

Gostaríamos de convidá-los para a próxima edição do SIES (Seminário Interinstitucional de Estudantes de Sistemas Dinâmicos), que será realizada no dia 28/08 (segunda-feira), a partir das 14h, no auditório da Pós-Graduação em Matemática (sala 407 do bloco H – Gragoatá).

Os palestrantes convidados serão: Matheus del Valle (IMPA), Lamartine Medeiros (UFRJ) e Caio Caetano (UFF).

Os resumos e detalhes das palestras podem ser encontrados no cartaz em abaixo.

Esperamos vocês!

SIES-2023-08-28Baixar

Hybrid BRAG Seminar – 25/08/23 – Cecília Salgado (University of Groningen) e Ethan Cotterill (UNICAMP)

Notícias, Seminários / Por

Olá a todos!

Temos o prazer de convidá-los para o Hybrid BRAG Seminar, que ocorrerá no dia 25 de agosto (sexta-feira), no auditório da Pós-Graduação em Matemática (Sala 407),  Bloco H – Gragoatá, a partir das 14h. 

Os palestrantes convidados são: Cecília Salgado (University of Groningen) e Ethan Cotterill (UNICAMP),

Seguem as informações abaixo:

14:00 – 15:00 BRT

Title: Mordell-Weil rank jumps on families of elliptic curves
Speaker: Cecília Salgado (University of Groningen)
Abstract: We will discuss recent advances around the variation of the Mordell-Weil rank in families of elliptic curves. The first part of the talk will be dedicated to introducing the theme, motivating, presenting the state of the art and a brief view on the different techniques used to deal with the problem. The second part will cover recent results on rank jumps on rational and K3 elliptic surfaces.

15:30 – 16:30 BRT

Title: Towards Brill–Noether theory for cuspidal curves
Speaker: Ethan Cotterill (Unicamp)
Abstract: Understanding when an abstract complex curve of given genus comes equipped with a map of fixed degree to a projective space of fixed dimension is a foundational question; and Brill–Noether theory addresses this question via linear series, which algebraically codify maps to projective targets. Classical Brill–Noether theory, which focuses on smooth curves, has been intensively explored; but much less is known for singular curves, particularly for those with non-nodal singularities. In this talk, we show how valuation-theoretic techniques may be used to study Brill–Noether-type varieties attached to cuspidal curves of geometric genus zero.

Everyone is welcome to come to UFF to attend the BRAG Seminar on Friday, August 25, 2023. Right after the seminars, we will gather for a happy hour at the Estúdio Onze Botequim, very close to Gragoatá Campus.

For those that cannot be at UFF for this occasion, it will be possible to attend the seminar virtually. The link with coordinates will be sent by email a few days before the seminar.

Check out the corresponding time at your time zone:
https://www.timeanddate.com/worldclock/fixedtime.html?msg=BRAG&iso=20230825T14&p1=570&ah=2&am=30

Webpages (with links to the slides and videos of previous talks):

https://sites.google.com/site/cotterillethan/ethan-cotterill-eng/brazilian-algebraic-geometry-seminar

https://researchseminars.org/seminar/BRAG

Previous talks available at the YouTube channel “Brazilian Algebraic Geometry”
https://www.youtube.com/channel/UCM-pcdNdpWxQFgOg-illE2w

Looking forward to seeing you all soon,
Organizers of the BRAG (Brazilian Algebraic Geometry).