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Oliver Labs: Cubic Surface Models and their Historical and Mathematical Background
In the 19th century, cubic surfaces - defined by an implicit equation of degree three in three variables - were among the first interesting examples in the development of modern algebraic geometry. A well-known result by Arthur Cayley and George Salmon is that any smooth cubic contains exactly 27 straight lines. Other prominent facts are the classification of all cubic surfaces w.r.t. their singularities by Ludwig Schläfli, and Alfred Clebsch's birational map between the plane and such surfaces where six points play an essential role. The talk will present both the historical and the mathematical background of classical hand-crafted and also recent 3d-printed cubic surface models. Some of their fascinating features such as the movement of the straight lines as the surfaces vary may very well be visualized using interactive software. In 2011 and 2014, the speaker created two versions of a complete series of more than 45 types of 3d-printed cubic surface models. Copies of these are now part of several university collections such as those at Lisbon, Strasbourg, Dresden, and Mainz, as well as at the IHP at Paris. He will bring some examples of these sculptures with him in order to illustrate facts which may better be appreciated when seeing and touching a real object.
Location: HS 001/Arnimallee 3 (Tea/coffee will be served from 16:45 in room 006/A3.)
Frank Neumann: Hochschild cohomology of dg-categories and spectral sequences
Location: SR 007/008, Arnimallee 6 (Tee/coffee will be served from 15:45 in room 006/A3)
Vincent Trageser: On actions of non-reductive groups with a graded unipotent radical on affine varieties
Location: SR 140, A3 (Hinterhaus)
Yorck Sommerhäuser: Hopf Algebras - A short introduction
Location: HS 001/A3 (Tee/coffee will be served from 15:45 in room 006/A3).
Bernd Kreussler: Means, Braids and Triangle Equations
Location: HS 001, A3 (Tea & coffee will be served from 4:45 pm in room 006, A3)
Alejandra Rincón Hidalgo: Bridgeland stability conditions on the n-Kronecker quiver
Location: SR 140, A3 (HH)
Hanxing Lin: Introduction to Cauchy-Pompeiu type formulas on Riemann surfaces
Location: SR 140, A3 (HH)
Heinrich Begehr: A hierarchy of complex partial differential operators II
Location: SR 140, A3 (HH)
Heinrich Begehr: A hierarchy of complex partial differential operators
Location: SR 140, A3 (HH)
Alejandra Rincón: Algebraic cycles and Roitman's theorem
Location: SR 025/026, Arnimallee 6.
Matthew Spong: Geometric Invariant Theory over the reals
Location: SR 005, Arnimallee 3
Nikolai Beck and Arijit Dey: Homotopic classification of vector bundles on smooth k-schemes
Location: SR 005, Arnimallee 3
Arijit Dey: Homotopic properties of the canonical torsor on the Grassmannians
Location: SR 005, Arnimallee 3
Victoria Hoskins: Anodyne extensions II
Location: SR 005, Arnimallee 3
Joana Cirici: Anodyne extensions
Location: SR 005, Arnimallee 3
Ángel Muñoz Castañeda: Excision for Picard groups and Karoubi-Villamayor K-theory
Abstract: We continue from last week by defining K_0 and K_1-regularity of a ring and prove that a regular ring is K_0 and K_1-regular. We show that distinguished squares of schemes give rise to an exact sequence relating their Picard groups and prove that K_0-regularity implies Pic-regularity. Then we define the Karoubi-Villamayor K-theory groups of a ring and relate these to the K_0 and K_1 groups. Further details: http://userpage.fu-berlin.de/hoskins/seminar.html [userpage.fu-berlin.de]
Location: Arnimalle 3, SR005
Ángel Muñoz Castañeda: K_0 and K_1 for rings
Location: SR 005, Arnimallee 3
Nickolai Beck: The A^1-homotopy category of smooth k-schemes
Location: SR 005, Arnimallee 3
Anna Wißdorf: The simplicial homotopy category of sheaves
Location: SR 005, Arnimallee 3
Eva Martínez: Sheaves in the Nisnevich topology
Location: SR 005, Arnimallee 3
Elena Martinengo: An introduction to homotopical algebra
Location: SR 005, Arnimallee 3
Vincent Trageser: Classification of principal bundles in algebraic topology
Location: Arnimalle 3, SR005
Victoria Hoskins: Introduction to A^1- homotopy theory of schemes
Location: SR 005, Arnimallee 3
Anna Wißdorf: The theorem of Mehta-Ramanathan
Location: Arnimallee 6, SR 025/026
Nikolai Beck: Wonderful compactifications
Location: Arnimallee 6, SR 025/026
Anna Wißdorf: Introduction to Arakelov Geometry II: Arakelov principal bundles
Location: Arnimallee 6, SR 025/026
Eva Martínez: Introduction to Arakelov Geometry I: Arakelov vector bundles over arithmetic curves
Location: Arnimallee 6, SR 025/026
Victoria Hoskins: Towards symplectic and hyperkähler quotients for non-reductive groups
Location: Arnimallee 6, SR 025/026
Anna Wißdorf: Betti numbers of the moduli space of Higgs bundles of rank 2 and degree 1
Location: Arnimallee 6, SR 025/026
Nikolai Beck: The gauge theoretic moduli space
Location: Arnimallee 6, SR 025/026
Joana Cirici: Hitchin's Existence Theorem
Location: Arnimallee 6, SR 025/026
Ángel Muñoz: Stability of Hitchin pairs
Location: Arnimallee 6, SR 025/026
Joana Cirici: Uhlenbeck’s Compactness Theorem
Location: Arnimallee 6, SR 025/026
Eva Martinez: Sobolev spaces of sections in fiber bundles
Location: Arnimallee 6, SR 025/026
Vincent Trageser: Review of classical Sobolev theory
Location: Arnimallee 6, SR 025/026
Ángel Muñoz: Hitchin’s self-duality equations
Location: Arnimallee 6, SR 025/026
Arijit Dey: Bundles on toric varieties
Location: Arnimallee 6, SR 025/026
Eva Martinez: Moduli spaces of stable rank 2 vector bundles on flag manifolds
Location: SR 005, Arnimallee 3
Juan Pons: Donaldson’s proof of Narasimhan-Seshadri
Location: SR 005, Arnimallee 3
Emilio Franco: Refined Hitchin-Kobayashi correspondence on elliptic curves
Location: SR 005, Arnimallee 3
Nikolai Beck: Gauge theory of fiber bundles
Location: SR 005, Arnimallee 3
Anna Wißdorf: The Theorem of Narasimhan and Seshadri
Location: SR 005, Arnimallee 3
Joana Cirici: Computing the E-polynomial of character varieties
Location: SR 005, Arnimallee 3
Juan Pons: Counting points of character varieties over finite fields.
Location: SR 005, Arnimallee 3
Daniela Prata (Campinas, Brazil)
Location: SR 005, Arnimallee 3
Simone Marchesi (Campinas Brazil)
Location: SR 130, Arnimallee 3, Hinterhaus
Ángel Muñoz: Abelianization of the Hitchin system
Location: SR 005, Arnimallee 3
Anna Wißdorf: Construction of the Harder-Narasimhan reduction
Location: SR 005, Arnimallee 3
Anna Wißdorf: The Harder–Narasimhan reduction of a Higgs bundle.
Location: SR 005, Arnimallee 3
Nickolai Beck: The moduli space of Higgs bundles.
Location: SR 005, Arnimallee 3
Anna Wißdorf: Symplectic and Orthogonal Instantons
Location: SR 025/026, Arnimallee 6
Nikolai Beck: Explicit Examples of Instanton Moduli Spaces II
Location: SR 025/026, Arnimallee 6
Nikolai Beck: Explicit Examples of Instanton Moduli Spaces
Location: Arnimallee 6, SR 025/026
Joanna Cirici: The Penrose Transform III : Cohomology and massless fields
Location: SR 025/026, Arnimallee 6
Patricia Borges dos Santos: Complex ADHM equations and sheaves on P^3
Location: Arnimallee 6, SR 025/026
Elena Martinengo: The Penrose Transformation
Location: Arnimallee 6, SR 025/026
Juan Pons Llopis: From Differential to Algebraic Geometry: Penrose Twistor Spaces
Location: Arnimallee 6, SR 025/026.
E.F.Gomez: Yang-Mills Equations and the Instanton Classification Problem
Location: Arnimallee 6, SR 025/026