Browsing by Snapshot Mathematical Subject "Geometry and Topology"

Now showing items 41-60 of 63

    • The periodic tables of algebraic geometry 

      [SNAP-2023-002-EN] Belmans, Pieter (Mathematisches Forschungsinstitut Oberwolfach, 2023-09-04)
      To understand our world, we classify things. A famous example is the periodic table of elements, which describes the properties of all known chemical elements and gives us a classification of the building blocks we can use ...

    • Polyhedra and commensurability 

      [SNAP-2016-009-EN] Guglielmetti, Rafael; Jacquement, Matthieu (Mathematisches Forschungsinstitut Oberwolfach, 2016)
      This snapshot introduces the notion of commensurability of polyhedra. At its bottom, this concept can be developed from constructions with paper, scissors, and glue. Starting with an elementary example, we formalize it ...

    • Positive Scalar Curvature and Applications 

      [SNAP-2019-004-EN] Rosenberg, Jonathan; Wraith, David (Mathematisches Forschungsinstitut Oberwolfach, 2019-04-25)
      We introduce the idea of curvature, including how it developed historically, and focus on the scalar curvature of a manifold. A major current research topic involves understanding positive scalar curvature. We discuss why ...

    • Das Problem der Kugelpackung 

      [SNAP-2016-004-DE] Dostert, Maria; Krupp, Stefan; Rolfes, Jan Hendrik (Mathematisches Forschungsinstitut Oberwolfach, 2016)
      Wie würdest du Tennisbälle oder Orangen stapeln? Oder allgemeiner formuliert: Wie dicht lassen sich identische 3-dimensionale Objekte überschneidungsfrei anordnen? Das Problem, welches auch Anwendungen in der digitalen ...

    • Profinite groups 

      [SNAP-2016-014-EN] Bartholdi, Laurent (Mathematisches Forschungsinstitut Oberwolfach, 2016)
      Profinite objects are mathematical constructions used to collect, in a uniform manner, facts about infinitely many finite objects. We shall review recent progress in the theory of profinite groups, due to Nikolov and Segal, ...

    • Random permutations 

      [SNAP-2019-007-EN] Betz, Volker (Mathematisches Forschungsinstitut Oberwolfach, 2019-07-12)
      100 people leave their hats at the door at a party and pick up a completely random hat when they leave. How likely is it that at least one of them will get back their own hat? If the hats carry name tags, how difficult ...

    • Reflections on hyperbolic space 

      [SNAP-2021-007-EN] Haensch, Anna (Mathematisches Forschungsinstitut Oberwolfach, 2021-08-24)
      In school, we learn that the interior angles of any triangle sum up to pi. However, there exist spaces different from the usual Euclidean space in which this is not true. One of these spaces is the ''hyperbolic space'', ...

    • Spaces of Riemannian metrics 

      [SNAP-2017-010-EN] Bustamante, Mauricio; Kordaß, Jan-Bernhard (Mathematisches Forschungsinstitut Oberwolfach, 2017-12-28)
      Riemannian metrics endow smooth manifolds such as surfaces with intrinsic geometric properties, for example with curvature. They also allow us to measure quantities like distances, angles and volumes. These are the ...

    • Swallowtail on the shore 

      [SNAP-2014-007-EN] Buchweitz, Ragnar-Olaf; Faber, Eleonore (Mathematisches Forschungsinstitut Oberwolfach, 2014)
      Platonic solids, Felix Klein, H.S.M. Coxeter and a flap of a swallowtail: The five Platonic solids tetrahedron, cube, octahedron, icosahedron and dodecahedron have always attracted much curiosity from mathematicians, not ...

    • Topological Complexity, Robotics and Social Choice 

      [SNAP-2018-005-EN] Carrasquel, José; Lupton, Gregory; Oprea, John (Mathematisches Forschungsinstitut Oberwolfach, 2018-08-10)
      Topological complexity is a number that measures how hard it is to plan motions (for robots, say) in terms of a particular space associated to the kind of motion to be planned. This is a burgeoning subject within the ...

    • Topological recursion 

      [SNAP-2018-002-EN] Sułkowski, Piotr (Mathematisches Forschungsinstitut Oberwolfach, 2018-03-05)
      In this snapshot we present the concept of topological recursion – a new, surprisingly powerful formalism at the border of mathematics and physics, which has been actively developed within the last decade. After introducing ...

    • Touching the transcendentals: tractional motion from the bir th of calculus to future perspectives 

      [SNAP-2019-013-EN] Milici, Pietro (Mathematisches Forschungsinstitut Oberwolfach, 2019-11-21)
      When the rigorous foundation of calculus was developed, it marked an epochal change in the approach of mathematicians to geometry. Tools from geometry had been one of the foundations of mathematics until the 17th century ...

    • Triangulations in geometry: from Ptolemy to Teichmüller 

      [SNAP-2026-004-EN] Pressland, Matthew (Mathematisches Forschungsinstitut Oberwolfach, 2026-02-27)
      Ptolemy's theorem is a classical result from ancient Greek mathematics, concerning the lengths of sides and diagonals of a polygon drawn in a circle. In this snapshot, I will explain why this theorem is still important ...

    • Trisections of four-dimensional spaces 

      [SNAP-2025-005-EN] Blackwell, Sarah (Mathematisches Forschungsinstitut Oberwolfach, 2025-09-19)
      This snapshot introduces the theory of trisections of smooth 4-manifolds, an area of exploration in low-dimensional topology aiming to make four-dimensional spaces more understandable. Along the way, we discuss the concepts ...

    • Tropical geometry 

      [SNAP-2018-007-EN] Brugallé, Erwan; Itenberg, Ilia; Shaw, Kristin; Viro, Oleg (Mathematisches Forschungsinstitut Oberwolfach, 2018-07-19)
      What kind of strange spaces hide behind the enigmatic name of tropical geometry? In the tropics, just as in other geometries, one of the simplest objects is a line. Therefore, we begin our exploration by considering tropical ...

    • Vertex-to-self trajectories on the platonic solids 

      [SNAP-2020-003-EN] Athreya, Jayadev S.; Aulicino, David (Mathematisches Forschungsinstitut Oberwolfach, 2020-04-15)
      We consider the problem of walking in a straight line on the surface of a Platonic solid. While the tetrahedron, octahedron, cube, and icosahedron all exhibit the same behavior, we find a remarkable difference with the ...

    • Voronoi cells: or how to find the nearest bakery 

      [SNAP-2024-003-EN] Hess, Sarah; Torres, Angélica; van der Eyden, Mirte (Mathematisches Forschungsinstitut Oberwolfach, 2024-09-05)
      Deciding which mall, hospital or school is closest to us is a problem we face everyday. It even comes on holidays with us, when we optimize our plans to make sure that we have enough time to visit all the attractions we ...

    • Waves and incidences 

      [SNAP-2024-001-EN] Yung, Po-Lam (Mathematisches Forschungsinstitut Oberwolfach, 2024-04-09)
      The wave equation in Euclidean spaces describes many natural phenomena such as sound, light, or water waves. We explore how its solutions are related to the geometric problem of how long thin cylinders can intersect each ...

    • What is pattern? 

      [SNAP-2022-009-EN] Baake, Michael; Grimm, Uwe; Moody, Robert V. (Mathematisches Forschungsinstitut Oberwolfach, 2022-10-25)
      Pattern is ubiquitous and seems totally familiar. Yet if we ask what it is, we find a bewildering collection of answers. Here we suggest that there is a common thread, and it revolves around dynamics.

    • The Willmore Conjecture 

      [SNAP-2016-011-EN] Nowaczyk, Nikolai (Mathematisches Forschungsinstitut Oberwolfach, 2016)
      The Willmore problem studies which torus has the least amount of bending energy. We explain how to think of a torus as a donut-shaped surface and how the intuitive notion of bending has been studied by mathematics over time.