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Now showing 1 - 10 of 25
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    Higgs bundles without geometry
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2020) Rayan, Steven; Schaposnik, Laura P.
    Higgs bundles appeared a few decades ago as solutions to certain equations from physics and have attracted much attention in geometry as well as other areas of mathematics and physics. Here, we take a very informal stroll through some aspects of linear algebra that anticipate the deeper structure in the moduli space of Higgs bundles.
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    From Betti numbers to ℓ²-Betti numbers
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2020) Kammeyer, Holger; Sauer, Roman
    We provide a leisurely introduction to ℓ²-Betti numbers, which are topological invariants, by relating them to their much older cousins, Betti numbers. In the end we present an open research problem about ℓ²-Betti numbers.
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    Quantum symmetry
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2020) Caspers, Martijn
    The symmetry of objects plays a crucial role in many branches of mathematics and physics. It allowed, for example, the early prediction of the existence of new small particles. “Quantum symmetry” concerns a generalized notion of symmetry. It is an abstract way of characterizing the symmetry of a much richer class of mathematical and physical objects. In this snapshot we explain how quantum symmetry emerges as matrix symmetries using a famous example: Mermin’s magic square. It shows that quantum symmetries can solve problems that lie beyond the reach of classical symmetries, showing that quantum symmetries play a central role in modern mathematics.
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    Describing distance: from the plane to spectral triples
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2021) Arici, Francesca; Mesland, Bram
    Geometry draws its power from the abstract structures that govern the shapes found in the real world. These abstractions often provide deeper insights into the underlying mathematical objects. In this snapshot, we give a glimpse into how certain “curved spaces” called manifolds can be better understood by looking at the (complex) differentiable functions they admit.
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    C∗ -algebras: structure and classification
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2021) Kerr, David
    The theory of C∗C∗-algebras traces its origins back to the development of quantum mechanics and it has evolved into a large and highly active field of mathematics. Much of the progress over the last couple of decades has been driven by an ambitious program of classification launched by George A. Elliott in the 1980s, and just recently this project has succeeded in achieving one of its central goals in an unexpectedly dramatic fashion. This Snapshot aims to recount some of the fundamental ideas at play.
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    Searching for the Monster in the Trees
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2022) Craven, David A.
    The Monster finite simple group is almost unimaginably large, with about 8 × 1053 elements in it. Trying to understand such an immense object requires both theory and computer programs. In this snapshot, we discuss finite groups, representations, and finally Brauer trees, which offer some new understanding of this vast and intricate structure.
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    Lagrangian mean curvature flow
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2021) Lotay, Jason D.
    Lagrangian mean curvature flow is a powerful tool in modern mathematics with connections to topics in analysis, geometry, topology and mathematical physics. I will describe some of the key aspects of Lagrangian mean curvature flow, some recent progress, and some major open problems.
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    The Enigma behind the Good–Turing formula
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2021) Balabdaoui, Fadoua; Kulagina, Yulia
    Finding the total number of species in a population based on a finite sample is a difficult but practically important problem. In this snapshot, we will attempt to shed light on how during World War II, two cryptanalysts, Irving J. Good and Alan M. Turing, discovered one of the most widely applied formulas in statistics. The formula estimates the probability of missing some of the species in a sample drawn from a heterogeneous population. We will provide some intuition behind the formula, show its wide range of applications, and give a few technical details.
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    Shape space – a paradigm for character animation in computer graphics
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2020) Heeren, Behrend; Rumpf, Martin
    Nowadays 3D computer animation is increasingly realistic as the models used for the characters become more and more complex. These models are typically represented by meshes of hundreds of thousands or even millions of triangles. The mathematical notion of a shape space allows us to effectively model, manipulate, and animate such meshes. Once an appropriate notion of dissimilarity measure between different triangular meshes is defined, various useful tools in character modeling and animation turn out to coincide with basic geometric operations derived from this definition.
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    Searching for structure in complex data: a modern statistical quest
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach gGmbH, 2021) Loh, Po-Ling
    Current research in statistics has taken interesting new directions, as data collected from scientific studies has become increasingly complex. At first glance, the number of experiments conducted by a scientist must be fairly large in order for a statistician to draw correct conclusions based on noisy measurements of a large number of factors. However, statisticians may often uncover simpler structure in the data, enabling accurate statistical inference based on relatively few experiments. In this snapshot, we will introduce the concept of high-dimensional statistical estimation via optimization, and illustrate this principle using an example from medical imaging. We will also present several open questions which are actively being studied by researchers in statistics.