Universidad de Granada

Complete meromorphic curves with Jordan boundaries

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modality
In person
speaker
Tjaša Vrhovnik
description

Geometry seminar

Speaker: Tjaša Vrhovnik

Abstract:We prove that given a finite set \(E\) in a bordered Riemann surface $\mathcal{R}$, there is a continuous map \(h\colon \overline{\mathcal{R}}\setminus E\to\mathbb{C}^n\) (\(n\geq 2\)) such that \(h|_{\mathcal{R}\setminus E} \colon \mathcal{R}\setminus E\to\mathbb{C}^n\) is a complete holomorphic immersion (embedding if \(n\geq 3\)) which is meromorphic on \(\mathcal{R}\) and has effective poles at all points in \(E\), and \(h|_{b\overline{\mathcal{R}}} \colon b\overline{\mathcal{R}}\to\mathbb{C}^n\) is a topological embedding. In particular, \(h(b\overline{\mathcal{R}})\) consists of the union of finitely many pairwise disjoint Jordan curves which we ensure to be of Hausdorff dimension one. We establish a more general result including uniform approximation and interpolation.

activity type

Riemann surfaces and some fundamental results.

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modality
In person
speaker
Jorge Hidalgo
description

Speaker: Jorge Hidalgo (Universidad de Granada)

Abstract: Riemann surfaces were first introduced in 1851, in the doctoral thesis of Bernhard Riemann, as a tool to study complex variable functions. Nowadays, Riemann surfaces constitute a whole theory in its own right, and a very fruitful one since it lies in the intersection of many important areas of mathematics. In particular, they connect geometry with complex analysis. The main goal of this talk is to give an overview about Riemann surface theory, which naturally splits into the two following steps:

  • To motivate and define the concept of Riemann surface, as well as other basic notions.
  • To understand the statements (and in some cases the idea) of several fundamental results. If time allows it, I will also give an idea of the relation between Riemann surfaces and my research, the first being a natural object to work with.
  • activity type

    Stable complete minimal hypersurfaces of \(\mathbb{R}^4\)

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    modality
    In person
    speaker
    Francisco Urbano
    description

    Seminario de Geometría

    Speaker: Francisco Urbano

    Abstract: We explain Catino, Mastrolia, and Roncoroni's proof that the hyperplanes are the only orientable stable complete minimal hypersurfaces of \(\mathbb{R}^4\)

    activity type

    Retracciones Lipschitz a subconjuntos compactos.

    date
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    modality
    In person
    speaker
    Rubén Medina
    description

    Seminario de Jóvenes Investigadores

    Título: Retracciones Lipschitz a subconjuntos compactos.

    Resumen: En 2014, Godefroy y Ozawa preguntaron si todo espacio de Banach separable admitía un retracto Lipschitz a un subconjunto compacto, convexo y linealmente denso. Encontrar este tipo de retractos dota a los espacios de una estructura 'compacta' a partir de la cual la intuición finitodimensional puede ser trasladada, algo semejante a lo que ocurre con los espacios con base de Schauder. Probamos que todo espacio con base de Schauder y, más aún, con descomposiciones de Schauder admiten un tal retracto Lipschitz. Además, probamos que los espacios de Banach sin la propiedad de aproximación acotada no admiten como retracto Lipschitz a gran parte de sus subconjuntos compactos y convexos. Este trabajo ha sido llevado a cabo durante la colaboración con Petr Hájek, Czech Technical University in Prague.

    La ponencia también podrá seguirse a través del enlace https://meet.google.com/yrc-wpte-dbj

    activity type

    Generalized Henneberg stable minimal surfaces

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    modality
    In person
    speaker
    David Moya
    description

    Seminario de Geometría

    Speaker: David Moya

    Abstract: In this talk we generalized the classical Henneberg minimal surface by giving an infinite family of complete, finitely branched, non-orientable, stable minimal surfaces in \(\mathbb{R}^3\). These surfaces can be grouped into subfamilies depending on a positive integer \(m\), which essentially measures the number of branch points. We describe the isometry group of the most symmetric example \(H_m\). The surfaces \(H_m\) can also be seeing either as the unique solution to a Björling problem for an hypocycloid of \(m+1\) cups if \(m\) is even or as the conjugate minimal surface to the unique solution to a Björling problem for an hypocycloid of \(2m+2\) cups if \(m\) is odd.

    activity type

    Maps preserving two-sided zero products on zero product determined Banach algebras

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    modality
    In person
    speaker
    Marisa C. Godoy
    description

    Seminario de Jóvenes Investigadores

    Speaker: Marisa C. Godoy, Universidad de Granada

    Abstract: Let A and B be Banach algebras and let Φ: A → B be a surjective continuous linear map which preserves two-sided zero products (i.e., Φ(a)Φ(b) = Φ(b)Φ(a) = 0 whenever ab = ba = 0). We show that Φ is a weighted Jordan homomorphism provided that A is zero product determined, is weakly amenable and admits a bounded approximate identity. These conditions are in particular fulfilled when A is the group algebra L¹(G) with G any locally compact group or a C*-algebra.

    Where: Seminario 2

    activity type

    "Overdetermined elliptic problems in onduloid-type domains with general nonlinearities".

    date
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    modality
    In person
    speaker
    Jing Wu
    description

    Seminario de Jóvenes Investigadores

    Resumen: In this talk we shall show a proof for the existence of solutions to a general semilinear elliptic problem with overdetermined boundary conditions. The proof uses a local bifurcation argument from the straight cylinder, in analogy with the onduloids and the theory of Constant Mean Curvature surfaces. Such examples have been found already for linear problems or with nonlinearity \(f(u)=1\). In this work we are able to extend this phenomenon for a large class of functions \(f(u)\).

    activity type

    "A Weierstrass type representation for translating solitons and singular minimal surfaces".

    date
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    modality
    In person
    speaker
    Antonio Martínez-Triviño
    description

    Seminario de Geometría

    Resumen: In this talk, we present a Weierstrass representation formula for translating solitons and singular minimal surfaces in \(\mathbb{R}^{3}\). As application, we study when the euclidean Gauss map has harmonic argument and solve a general Cauchy's problem in this class of surfaces.

    Lugar: Sala de Conferencias

    Acceso Online: Sala EINSTEIN UGR. Para entrar en la reunión, pulse el siguiente enlace: https://oficinavirtual.ugr.es/redes/SOR/SALVEUGR/accesosala.jsp?IDSALA=22985198

    Contraseña: 938641

    host
    Antonio Alarcón
    activity type

    Seminario de Geometría

    date
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    modality
    In person
    description
    Título: El teorema de Spruck y Xiao para solitones del flujo por la curvatura media
    Impartida por: Francisco Martín
    Resumen:

    Spruck y Xiao demostraron en 2018 que todo solitón por traslación del FCM en \(\mathbb{R}^3\) que sea un grafo completo tiene que ser convexo (\(K \geq 0\)). Nosotros daremos una demostración alternativa de ese teorema, basada en un trabajo conjunto con D. Hoffman y B. White.


    13 de diciembre de 2019, 12:30, Seminario de la 2º planta del IEMath-GR
    activity type