Álvaro Martínez-Pérez

  1. Bounded distortion homeomorphisms on ultrametric spaces.

    Authors: Álvaro Martínez-Pérez, Bruce Hughes, Manuel A. Morón
    Subjects: Metric Geometry
    Abstract

    It is well-known that quasi-isometries between R-trees induce power
    quasi-symmetric homeomorphisms between their ultrametric end spaces. This paper
    investigates power quasi-symmetric homeomorphisms between bounded, complete,
    uniformly perfect, ultrametric spaces (i.e., those ultrametric spaces arising
    up to similarity as the end spaces of bushy trees). A bounded distortion
    property is found that characterizes power quasi-symmetric homeomorphisms
    between such ultrametric spaces that are also pseudo-doubling.

  2. A metric between quasi-isometric trees.

    Authors: Álvaro Martínez-Pérez
    Subjects: Geometric Topology
    Abstract

    It is known that PQ-symmetric maps on the boundary characterize the
    quasi-isometry type of visual hyperbolic spaces, in particular, of geodesically
    complete \br-trees. We define a map on pairs of PQ-symmetric ultrametric spaces
    which characterizes the branching of the space. We also show that, when the
    ultrametric spaces are the corresponding end spaces, this map defines a metric
    between rooted geodesically complete simplicial trees with minimal vertex
    degree 3 in the same quasi-isometry class. Moreover, this metric measures how
    far are the trees from being rooted isometric.

  3. Zig-zag chains and metric equivalences between ultrametric spaces.

    Authors: Álvaro Martínez-Pérez
    Subjects: Geometric Topology
    Abstract

    We study the classification of ultrametric spaces based on their small scale
    geometry (uniform homeomorphism), large scale geometry (coarse equivalence) and
    both (all scale uniform equivalences). We prove that these equivalences can be
    characterized with parallel constructions using a combinatoric tool called
    common zig-zag chain.

  4. Zig-zag chains and metric equivalences between ultrametric spaces.

    Authors: Álvaro Martínez-Pérez
    Subjects: Geometric Topology
    Abstract

    We study the classification of ultrametric spaces based on their small scale
    geometry (uniform homeomorphism), large scale geometry (coarse equivalence) and
    both (all scale uniform equivalences). We prove that these equivalences can be
    characterized with parallel constructions using a combinatoric tool called
    common zig-zag chain.

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