Conferències | Blog de la Biblioteca de Matemàtiques i Informàtica

10/02/2020
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SIMBa: An introduction to Floer theory

El proper dimecres, 12 de febrer, se celebrarà una nova xerrada del Seminari Informal de Matemàtiques de Barcelona (SIMBa).

Speaker: Joaquim Brugués
Universitat: Universitat Politècnica de Catalunya.

Data: Wednesday, 12th of February
Hora: 12:00, coffee break (be eco friendly, bring your cup); 12:20, talk.
Lloc: B1 classroom, Facultat de Matemàtiques de la Universitat de Barcelona.
Idioma: English

Títol: An introduction to Floer theory
Resum: The development of Floer theory is a history of collaboration andintersection of ideas that starts with a conjecture by Arnold in1966 on a Morse-like lower bound on the number of fixed points ofa symplectomorphism. The efforts to prove this conjecture (now atheorem) motivated the development of tools that are still essentialin symplectic topology investigation. In this talk we aim to presentthe conjecture and sumarize the history, ending with the definitionof Floer homology.

Si voleu estar al cas de les xerrades previstes, podeu consultar el calendari. Si voleu proposar una xerrada, ompliu el formulari. Si voleu contactar amb els responsables podeu escriure un missatge a seminari(dot)simba(at)ub(dot)edu.

28/01/2020
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SIMBa: Morse theory: from dynamics to topology and back

El proper dimecres, 29 de gener, se celebrarà una nova xerrada del Seminari Informal de Matemàtiques de Barcelona (SIMBa).

Speaker: Joaquim Brugués
Universitat: Universitat Politècnica de Catalunya.

Data: Wednesday, 29th of January
Hora: 12:00, coffee break (be eco friendly, bring your cup); 12:20, talk.
Lloc: S1 classroom, Facultat de Matemàtiques de la Universitat de Barcelona.
Idioma: English

Títol: Morse theory: from dynamics to topology and back
Resum: Morse theory relates the critical points of a smooth function defi-ned on a manifold to the topology of the manifold, in a way thatallows to construct a homology equivalent to the singular homo-logy from classical algebraic topology. The main result from thisconstruction are the Morse inequalities, that give a lower boundon the number of critical points of a smooth function that dependssolely on the underlying topology. In this talk we will present theideas behind this construction and the most remarkable results ofthe theory. It’s recommended to have some previous knowledgeof differential geometry and/or algebraic topology to understandthis talk.

25/11/2019
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SIMBa: Postquantum cryptography: what, why, and how?

El proper dimecres, 27 de novembre, se celebrarà una nova xerrada del Seminari Informal de Matemàtiques de Barcelona (SIMBa).

Speaker: Enric Florit Zacarías
Universitat: Universitat de Barcelona

Data: Wednesday, 27th of November
Hora: 12:00, coffee break; 12:20, talk
Lloc: Aula B1 Facultat de Matemàtiques de la Universitat de Barcelona.
Idioma: English

Títol: Postquantum cryptography: what, why, and how?
Resum: The key agreement scheme proposed by Diffie and Hellman in 1976 relies on the problem of finding discrete logarithms. One can choose appropriate groups where the best algorithms for solving this problem are too slow, such as certain elliptic curves over finite fields. There are already proposed quantum algorithms that break discrete logarithms in polynomial time. For this reason multiple “post-quantum” cryptography primitives have appeared in the last years, while trying to find harder computational problems. One of the proposed protocols using elliptic curves is SIDH/SIKE, candidate to the NIST Post-Quantum Cryptography Competition.

10/06/2019
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SIMBa: Isogenies and Cryptography

El proper dimecres, 12 de juny, se celebrarà una nova xerrada del Seminari Informal de Matemàtiques de Barcelona (SIMBa).

Speaker: Coral Real Llamas
Universitat: Eurecat – Centre Tecnològic de Catalunya

Data: Dimecres, 12 de juny de 2019
Hora: 12:00, cafè; 12:20, xerrada
Lloc: Aula B1 Facultat de Matemàtiques de la Universitat de Barcelona.
Idioma: Castellà

Títol: Isogenies and Cryptography
Resum: Nowadays in post-quantum cryptography the use of isogenies isincreasing. They are used in key exchange or in signature sc-hemes. After a brief introduction to the concept of isogeny, inthis talk we explain how they are being used in quantum-resistantcryptography.

03/06/2019
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SIMBa: On an efficient implementation of the Roe scheme for large hyper-bolic systems

El proper dimecres, 5 de juny, se celebrarà una nova xerrada del Seminari Informal de Matemàtiques de Barcelona (SIMBa).

Speaker: Ernesto Pimentel García
Universitat: Universidad de Málaga

Data: Dimecres, 5 de juny de 2019
Hora: 12:00, cafè; 12:20, xerrada
Lloc: Aula B1 Facultat de Matemàtiques de la Universitat de Barcelona.
Idioma: Anglès

Títol: On an efficient implementation of the Roe scheme for large hyper-bolic systems
Resum: There exist several schemes to solve numerically hyperbolic sys-tems of Partial Differencial Equations. Two of them are the Sim-ple Riemann solvers (SRS) and the Polynomial Viscosity matrix(PVM) methods.
The results obtained by Morales de Luna et al. (2014) concerningthe relation between SRS and the PVM methods are revisited andapplied to the efficient implementation of the Roe method for largehyperbolic systems either conservative or non-conservative. Thisimplementation, based on the Newton’s form of the interpolationpolynomial, will be applied to the two-layer shallow water modeland a non-conservative model for rarefied gas flow.

15/04/2019
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SIMBa: Factorización de un morfismo

El proper dimecres, 24 d’abril, se celebrarà una nova xerrada del Seminari Informal de Matemàtiques de Barcelona (SIMBa).

Speaker: Wilson Forero
Universitat: Universitat Autònoma de Barcelona

Data: Dimecres, 24 d’abril de 2019
Hora: 12:00, cafè; 12:20, xerrada
Lloc: Aula B1 Facultat de Matemàtiques de la Universitat de Barcelona.
Idioma: Castellà

Títol: Factorización de un morfismo
Resum: Al estudiar una función entre conjuntos es posible factorizarla por medio de su imagen, esta construcción se puede generalizar a la teoría de categorías debido a su comportamiento functorial, en donde a un morfismo arbitrario se le asigna la categoría de todas sus posibles factorizaciones; además, esta construcción también se puede llevar al caso simplicial. En esta charla daré un esbozo de las ideas que llevaron a este resultado.

09/04/2019
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SIMBa: Studying the Fatou set for a generalization of Milnor’s family ofcubic maps

El proper dimecres, 10 d’abril, se celebrarà una nova xerrada del Seminari Informal de Matemàtiques de Barcelona (SIMBa).

Speaker: Dan Alexandru Paraschiv
Universitat: Universitat de Barcelona

Data: Dimecres, 10 d’abril de 2019
Hora: 12:00, cafè; 12:20, xerrada
Lloc: Aula B1 Facultat de Matemàtiques de la Universitat de Barcelona.
Idioma: Anglès

Títol: Studying the Fatou set for a generalization of Milnor’s family ofcubic maps.
Resum: The first attempts of studying iteration of holomorphic functionswere succesfully realized by Julia and Fatou in the 1920s. However,due to technological limitations, having a good intuition of thearising fractal-like patterns was very difficult, and the problemstarted being studied again in the 1980s by Mandelbrot, startingwith the quadratic family $P_{c}=z^{2} + c$ , where $c \in \mathbb{C}$ .

Nowadays, among rational maps on the Riemann sphere, a heigh-tened interest in perturbation maps exist. We’ll summarilly introduce 3 families of maps (2 with perturbations, one of polynomials of degree 3) which are helpful in understanding ourwork. We will conclude with some results obtained by us for aspecific case of perturbation of bicritical hyperbolic polynomials ( $D_\lambda = z^{n+1}- az^{n} + \frac{\lambda}{z^d}$ for fixed $a$ belonging to a specific hyperbolic component of the parameter plane of $M_a = z^{n+1} - az^{n},\lambda$ small enough and $n,d$ natural numbers such that $\frac{1}{n}+\frac{1}{2}<1)$ .