• Algebra, matrices, and computers 

      [SNAP-2019-005-EN] Detinko, Alla; Flannery, Dane; Hulpke, Alexander (Mathematisches Forschungsinstitut Oberwolfach, 2019-05-03)
      What part does algebra play in representing the real world abstractly? How can algebra be used to solve hard mathematical problems with the aid of modern computing technology? We provide answers to these questions that ...
    • Analogue mathematical instruments: Examples from the “theoretical dynamics” group (France, 1948–1964) 

      [SNAP-2019-012-EN] Petitgirard, Loïc (Mathematisches Forschungsinstitut Oberwolfach, 2019-11-21)
      Throughout the history of dynamical systems, instruments have been used to calculate and visualize (approximate) solutions of differential equations. Here we describe the approach of a group of physicists and engineers ...
    • Billard und ebene Flächen 

      [SNAP-2015-001-DE] Davis, Diana (Mathematisches Forschungsinstitut Oberwolfach, 2015)
      Billard, die Zick-Zack-Bewegungen eines Balls auf einem Tisch, ist ein reichhaltiges Feld gegenwärtiger mathematischer Forschung. In diesem Artikel diskutieren wir Fragen und Antworten zum Thema Billard, und zu dem damit ...
    • Billiards and flat surfaces 

      [SNAP-2015-001-EN] Davis, Diana (Mathematisches Forschungsinstitut Oberwolfach, 2015)
      Billiards, the study of a ball bouncing around on a table, is a rich area of current mathematical research. We discuss questions and results on billiards, and on the related topic of flat surfaces.
    • Braid groups, the Yang–Baxter equation, and subfactors 

      [SNAP-2021-005-EN] Lechner, Gandalf (Mathematisches Forschungsinstitut Oberwolfach, 2021)
      The Yang–Baxter equation is a fascinating equation that appears in many areas of physics and mathematics and is best represented diagramatically. This snapshot connects the mathematics of braiding hair to the Yang–Baxter ...
    • $C^*$-algebras: structure and classification 

      [SNAP-2021-002-EN] Kerr, David (Mathematisches Forschungsinstitut Oberwolfach, 2021-02-23)
      The theory of $C^*$-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 ...
    • Closed geodesics on surfaces and Riemannian manifolds 

      [SNAP-2017-005-EN] Radeschi, Marco (Mathematisches Forschungsinstitut Oberwolfach, 2017-12-07)
      Geodesics are special paths in surfaces and so-called Riemannian manifolds which connect close points in the shortest way. Closed geodesics are geodesics which go back to where they started. In this snapshot we talk ...
    • Computing the long term evolution of the solar system with geometric numerical integrators 

      [SNAP-2017-009-EN] Fiorelli Vilmart, Shaula; Vilmart, Gilles (Mathematisches Forschungsinstitut Oberwolfach, 2017-12-27)
      Simulating the dynamics of the Sun–Earth–Moon system with a standard algorithm yields a dramatically wrong solution, predicting that the Moon is ejected from its orbit. In contrast, a well chosen algorithm with the ...
    • Configuration spaces and braid groups 

      [SNAP-2019-011-EN] Jiménez Rolland, Rita; Xicoténcatl, Miguel A. (Mathematisches Forschungsinstitut Oberwolfach, 2019-10-08)
      In this snapshot we introduce configuration spaces and explain how a mathematician studies their ‘shape’. This will lead us to consider paths of configurations and braid groups, and to explore how algebraic properties of ...
    • Counting self-avoiding walks on the hexagonal lattice 

      [SNAP-2019-006-EN] Duminil-Copin, Hugo (Mathematisches Forschungsinstitut Oberwolfach, 2019-06-04)
      In how many ways can you go for a walk along a lattice grid in such a way that you never meet your own trail? In this snapshot, we describe some combinatorial and statistical aspects of these so-called self-avoiding ...
    • Curvatura escalar positiva y aplicaciones 

      [SNAP-2019-004-ES] Rosenberg, Jonathan; Wraith, David (Mathematisches Forschungsinstitut Oberwolfach, 2021)
      Introducimos la idea de curvatura, incluyendo su desarrollo histórico, y nos enfocamos en la curvatura escalar de una variedad. Uno de los temas principales de investigación actual es entender la curvatura escalar positiva. ...
    • Deep Learning and Inverse Problems 

      [SNAP-2019-015-EN] Arridge, Simon; de Hoop, Maarten; Maass, Peter; Öktem, Ozan; Schönlieb, Carola; Unser, Michael (Mathematisches Forschungsinstitut Oberwolfach, 2019-11-21)
      Big data and deep learning are modern buzz words which presently infiltrate all fields of science and technology. These new concepts are impressive in terms of the stunning results they achieve for a large variety of ...
    • Describing distance: from the plane to spectral triples 

      [SNAP-2021-009-EN] Arici, Francesca; Mesland, Bram (Mathematisches Forschungsinstitut Oberwolfach, 2021-12-31)
      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 ...
    • Determinacy versus indeterminacy 

      [SNAP-2020-004-EN] Berg, Christian (Mathematisches Forschungsinstitut Oberwolfach, 2020-04-22)
      Can a continuous function on an interval be uniquely determined if we know all the integrals of the function against the natural powers of the variable? Following Weierstrass and Stieltjes, we show that the answer is yes ...
    • Diophantine equations and why they are hard 

      [SNAP-2019-003-EN] Pasten, Hector (Mathematisches Forschungsinstitut Oberwolfach, 2019-04-24)
      Diophantine equations are polynomial equations whose solutions are required to be integer numbers. They have captured the attention of mathematicians during millennia and are at the center of much of contemporary research. ...
    • The Enigma behind the Good–Turing formula 

      [SNAP-2021-008-EN] Balabdaoui, Fadoua; Kulagina, Yulia (Mathematisches Forschungsinstitut Oberwolfach, 2021-07-16)
      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, ...
    • Espacios de métricas Riemannianas 

      [SNAP-2017-010-ES] Bustamante, Mauricio; Kordaß, Jan-Bernhard (Mathematisches Forschungsinstitut Oberwolfach, 2021)
      Las métricas riemannianas dan a las variedades suaves, como las superficies, propiedades geométricas intrínsecas, por ejemplo la curvatura. También permiten medir cantidades como distancias, ángulos y volúmenes. Estas son ...
    • Expander graphs and where to find them 

      [SNAP-2019-016-EN] Khukhro, Ana (Mathematisches Forschungsinstitut Oberwolfach, 2019-11-22)
      Graphs are mathematical objects composed of a collection of “dots” called vertices, some of which are joined by lines called edges. Graphs are ideal for visually representing relations between things, and mathematical ...
    • Finite geometries: pure mathematics close to applications 

      [SNAP-2021-010-EN] Storme, Leo (Mathematisches Forschungsinstitut Oberwolfach, 2021-09-22)
      The research field of finite geometries investigates structures with a finite number of objects. Classical examples include vector spaces, projective spaces, and affine spaces over finite fields. Although many of these ...
    • Formation Control and Rigidity Theory 

      [SNAP-2019-017-EN] Zelazo, Daniel; Zhao, Shiyu (Mathematisches Forschungsinstitut Oberwolfach, 2019-12-11)
      Formation control is one of the fundamental coordination tasks for teams of autonomous vehicles. Autonomous formations are used in applications ranging from search-and-rescue operations to deep space exploration, with ...