# Dates

### Habilitation Jean-Philippe Labbé

Location: WebEx Please ask a member of the work group for further information (e.g. Jonathan Kliem).

### Disputation Giulia Codenotti

Thema der Dissertation: Covering properties of lattice polytopes Thema der Disputation: Triangulations of products of simplices and the spread out simplices conjecture

Location: Arnimallee 3, SR 019

### Disputation Jorge Olarte

Location: Arnimallee 3, SR 119

### Einstein Workshop Polytopes and Algebraic Geometry 2019

This will be a three-day workshop with lectures, presentations and informal discussions on polytopes and their relations to algebraic geometry. It is funded by the Einstein Foundation Berlin , as part of Francisco Santos' Einstein Visiting Fellowship at FU Berlin for 2016-2020. It is one of the activities in the thematic Einstein semester Varieties Polyhedra and computations .

### Einstein Workshop Geometric and Topological Combinatorics

Location: Freie Universität Berlin, Königin Luise Straße 24/26, 14195 Berlin

### Encuentro Colombiano de Combinatoria ECCO 2018

Günter M. Ziegler (FU Berlin): „Polytopes — Extremal Examples and Combinatorial Parameters“

Location: Universidad del Norte, Barranquilla, Colombia

### Einstein Workshop Discrete Geometry and Topology

This will be a four day workshop with lectures, presentations and informal discussions on discrete geometry and topology, and related topics (combinatorial topology, computational geometry, polytope theory). It is primarily funded by the Einstein Foundation Berlin , as part of Francisco Santos' Einstein Visiting Fellowship at FU Berlin for 2016-2019. Additional funding is provided by the project Discretization in Geometry and Dynamics (SFB Transregio 109) and the Berlin Mathematical School . Read more.

Location: Freie Universität Berlin

### Defense Lauri Loiskekoski

Location: Seminar Room Arnimallee 2 14195 Berlin

### Open-Acess-World-Café

Location: Freie Universität Berlin, Seminarzentrum, Raum: L 113 und L 116 (Erdgeschoss), Otto-von-Simson-Str. 26 (Silberlaube), 14195 Berlin

### ÖMG-DMV-Jahrestagung 2017

Location: Paris-Lodron University of Salzburg

### MSRI Program „Geometric and Topological Combinatorics“

Location: MSRI, Berkeley

### Reading Group on Real Algebraic Geometry

Location: Max Planck Institute for Mathematics in the Sciences Inselstraße 22 04103 Leipzig Germany

### Conference on Applied Topology

Location: Banach Center, Będlewo, Polen

### Long Night of the Sciences

Location: Berlin

### Discrete Geometry and Convexity - BÁRÁNY 70

Location: Renyi Institute of Mathematics, Budapest

### Defense Albert Haase

The square peg problem is at least 106 years old and still unsolved in full generality. It asks whether any simple closed curve in the plane inscribes a square. By “inscribes a square” we mean that the curve contains the four vertices of a square. The square itself may intersect both the bounded and unbounded components. Substantial progress on the problem has been made using methods from equivariant topology: Piecewise linear, analytic, convex, and locally monotone curves are all known to inscribe squares. We present a recent positive result by T. Tao that takes an entirely different, “analytical” approach involving areas defined by line integrals and Stokes’ theorem.

Location: Seminar Room

### Polynomials and Polytopes

This is a workshop within the project on NonLinear Algebra that is funded for 2015-2018 by the Einstein Foundation . The workshop is also supported by the TU Berlin , the MPI for Mathematics in the Sciences in Leipzig, and the Emmy Noether Programm of the DFG .

Location: MA 144 Straße des 17. Juni 136 10623 Berlin

### Conference on Convex, Discrete and Integral Geometry

Location: Banach Center, Będlewo, Polen

### Jörgshop TU Berlin, 2017

Location: TU Berlin MA041 (ground floor) of the Mathematics Building Strasse des 17 Juni 136

### Seminar on Non-Linear Algebra

Location: MPI für Mathematik in den Naturwissenschaften Leipzig, E1 05 (Leibniz-Saal)

### Euler-Lecture

Location: Auditorium Maximum im Haus 8 der Universität Potsdam Am Neuen Palais 14476 Potsdam

### Defense Tobias Friedl

Location: Seminar Room

### Discrete Geometry Fest, Budapest

Location: Budapest

### Digital Future - Digital Science Match

Location: Berlin

### Workshop „Discrete Geometry“

Location: Mathematisches Forschungsinstitut Oberwolfach

### "You don't know what Math is….“ Ein Panorama der Mathematik

Location: Leipzig

### TU Dresden, Dresdner Mathematisches Seminar

Location: TU Dresden

### Salon Sophie Charlotte der BBAW

Location: Akademiegebäude am Gendarmenmarkt, Berlin

### Workshop „Combinatorics“

Location: Mathematisches Forschungsinstitut Oberwolfach

### Heidelberg Laureate Forum 2016

Location: Heidelberg

### ICME - Öffentlicher Vortrag

Location: Hamburg

### ICME - Öffentlicher Vortrag

Location: Hamburg

### ICME - Plenary Mathematics Lecture

Location: Hamburg

### ICME - Plenary Mathematics Lecture

Location: Hamburg

### Mathematics of Jirí Matoušek

Location: Charles University, Prague

### Mathematics of Jirí Matoušek

Location: Charles University, Prague

### 7th European Congress of Mathematics

Location: TU Berlin

### John von Neumann Lecture 2016

Location: Universität Münster

### John von Neumann Lecture 2016

Location: Universität Münster

### DMV & GAMM Jahrestagung

Location: TU Braunschweig

### Panorama der Mathematik, III: Über Fehler

Location: Urania Berlin

### Panorama der Mathematik, III: Über Fehler

Location: Urania Berlin

### DFG-Vortragsreihe "exkurs - Einblick in die Welt der Wissenschaft"

Location: Wissenschaftszentrum Bonn

### DFG-Vortragsreihe "exkurs - Einblick in die Welt der Wissenschaft"

Location: Wissenschaftszentrum Bonn

### Borel Seminar

Location: Les Diablerets, Switzerland

### “Combinatorics: Challenges and Applications” (Noga Alon 60 birthday)

Location: Tel Aviv University

### “Combinatorics: Challenges and Applications” (Noga Alon 60 birthday)

Location: Tel Aviv University

### Adventsbilder - Ist Mathematik doch eine Kunst?

Location: Urania Berlin

### Adventsbilder - Ist Mathematik doch eine Kunst?

Location: Urania Berlin

### Panorama der Mathematik, II: Was gibts Neues in der Mathematik?

Location: Urania Berlin

### Panorama der Mathematik, II: Was gibts Neues in der Mathematik?

Location: Urania Berlin

### 7. Thüringer Geometrietag

Location: Friedrich-Schiller-Universität, Jena

### Discrete Geometry Seminar - Moritz Schmitt

Location: Seminar Room, Arnimallee 2, FU Berlin

### Discrete Geometry Seminar - Michal Lason

Location: Seminar Room, Arnimallee 2, FU Berlin

### Discrete Geometry Seminar - Alexander Engström

Location: Seminar Room, Arnimallee 2, FU Berlin

### Geometry and Symmetry Conference

The conference will celebrate the 60th birthdays in 2015 of Karoly Bezdek (University of Calgary, Canada and University of Pannonia, Hungary) and Egon Schulte (Northeastern University, USA). The theme of the conference will be “Geometry and Symmetry”, with emphasis on recent progress on aspects of discrete geometry in which Egon and Karoly have made remarkable contributions. The program of the conference will consist of invited lectures and contributed talks.

Location: Veszprém, Hungary

### Tsukerman - Circumcenter of mass

Location: Seminar Room, Arnimallee 2, FU Berlin

### Lange Nacht der Wissenschaften

Location: Arnimallee 6, FU Berlin

### "What is ... group homology?" -- Peter Patzt (FU)

Location: @BMS Loft Urania

### Discrete Geometry Seminar- Samuel Fionrini

Location: Seminar Room, Arnimallee 2, FU Berlin

### Dressing code for the sphere - scribability problems of polytopes - Chen

Location: Seminar Room, Arnimallee 2, FU Berlin

### Distributed Processes on Scale-Free Networks -- Tobias Friedrich

Lecture - 14:15 Tobias Friedrich - HPI, Universität Potsdam Distributed Processes on Scale-Free Networks Abstract: The node degrees of large real-world networks often follow a power-law distribution. Such scale-free networks can be social networks, internet topologies, the web graph, power grids, or many other networks from literally hundreds of domains. The talk will introduce three mathematical models of scale-free networks (preferential attachment graphs, Chung-Lu graphs, hyperbolic random graphs) and analyze some of their properties. We then study three distributed processes and algorithms on these network models (rumor spreading, load balancing, de-anonymization) and present several open problems. The talk assumes no prior knowledge about scale-free networks or distributed computing. Colloquium - 16:00 Fidaa Abed - Technische Universität Berlin Optimal Coordination Mechanisms for Multi-Job Scheduling Games Abstract: We consider the unrelated machine scheduling game in which players control subsets of jobs. Each player's objective is to minimize the weighted sum of completion time of her jobs, while the social cost is the sum of players' costs. The goal is to design simple processing policies in the machines with small coordination ratio, i.e., the implied equilibria are within a small factor of the optimal schedule. We work with a weaker equilibrium concept that includes that of Nash. We first prove that if machines order jobs according to their processing time to weight ratio, a.k.a. Smith-rule, then the coordination ratio is at most 4, moreover this is best possible among nonpreemptive policies. Then we establish our main result. We design a preemptive policy, externality , that extends Smith-rule by adding extra delays on the jobs accounting for the negative externality they impose on other players.. For this policy we prove that the coordination ratio is 1+ φ ≈ 2.618, and complement this result by proving that this ratio is best possible even if we allow for randomization or full information. Finally, we establish that this externality policy induces a potential game and that an ε-equilibrium can be found in polynomial time. An interesting consequence of our results is that an ε-local optima of $R|\,|\sum w_jC_j$ for the jump (a.k.a. move) neighborhood can be found in polynomial time and are within a factor of 2.618 of the optimal solution. The latter constitutes the first direct application of purely game-theoretic ideas to the analysis of a well studied local search heuristic.

Location: @TU MA 041

### "What is ... a supercritical percolation cluster?" -- Nguyen Tuan Anh

Location: @TU MA 212

### The freeness of ideal subarrangements of Weyl arrangements - Torsten-Hoge

Location: Seminar Room, Arnimallee 2, FU Berlin

### A decomposition theory for vertex enumeration of convex polyhedra -- Leen Stougie

Location: @TU MA 041

### Hodge theory and combinatorics - Adiprasito

Location: Seminar Room, Arnimallee 2, FU Berlin

### ECMath Salon - Randbedingungen erfolgreicher Forschung

Location: Urania Berlin, BMS Lounge

### Seminar-Zero Sets of Polynomials Invariant under Finite Reflection Groups- Tobias Friedl

Location: Seminar Room, Arnimallee 2, FU Berlin

### Contact Representations of Planar Graphs -- Stefan Felsner

Location: @TU MA 041

### ERC Workshop "SD-Models"

Location: FU Berlin

### BMS Days - Berlin People, Projects, Opportunities

Location: BMS Loft in Urania

### Flag Vector Spaces of Polytopes, Spheres and Eulerian Lattices

Location: Seminar Room, Arnimallee 2, FU Berlin

### "What is ... (algebraic) complexity theory?" -- Jesko Hüttenhain (TU)

Location: BMS Loft in Urania

### Valuations on Lattice Polytopes

Location: @TU MA 041

### Moduli of Tropical Plane Curves- Sarah Brodsky

Location: Seminar Room, Arnimallee 2, FU Berlin

### Topology-Seminar-Configuration Spaces of Graphs

Location: Seminar room in the Villa, Arnimallee 2, 14195 Berlin

### What can be computed in algebraic geometry? -- Wolfram Decker

Location: @TU MA 041

### Preisverleihung

Location: TU Berlin, Audimax, Straße des 17. Juni 135

### "What is ... the probabilistic method?"

Location: @BMS Loft in Urania

### Congruence Arguments in the Geometry of Numbers and a General Discrete Minkowksi-type Theorem

Location: Seminar Room, Arnimallee 2, FU Berlin

### Improving bistellar simplification

Location: Seminar room in the Villa, Arnimallee 2, 14195 Berlin

### The 18th Midrasha Mathematicae

Location: Jerusalem

### "What is ... a van Kampen obstruction cocycle" -- Isaac Mabillard (IST Austria)

Location: @TU MA 313

### Generalized Schur-Horn orbitopes and zonoids

Location: Seminar Room, Arnimallee 2, FU Berlin

### Eliminating Tverberg Points: An Analogue of the Whitney Trick

Location: Seminar room in the Villa, Arnimallee 2, 14195 Berlin

### Phirotopes & Almost-Fisher Families

Location: Freie Universität Berlin, Takustr, 9, 14195 Berlin, room: 005

### Salon des Einstein-Zentrums Mathematik (ECMath)

Location: Urania Berlin, BMS Lounge, An der Urania 17, 10787 BErlin

### "What is ... sparse and redundant representation modeling for image processing?" -- Wang-Q Lim (TU)

Location: @BMS Loft in Urania

### Discrete Geometry Seminar- Victor M.Buchstaber

Location: Seminar Room, Arnimallee 2, FU Berlin

### The maximum likelihood degree and data discriminants of likelihood equations

Location: Seminar room in the Villa, Arnimallee 2, 14195 Berlin

### Geometrietag an der TU Dresden

Location: TU Dresden

### ICM 2014

Location: Seoul, Korea

### Dürer Lecture in New York

Vor 500 Jahren schuf Albrecht Dürer seine drei berühmten "Meisterstiche", darunter den Kupferstich "MELENCOLIA I". Dieses Jubiläum wurde am 17. Mai 2014 mit einer Konferenz "500 Years of Melancholia in Mathematics" in New York gefeiert. Aus diesem Anlass sprach Günter M. Ziegler, Professor für Diskrete Geometrie an der Freien Universität Berlin, über den Polyeder in der "MELENCOLIA I". Hier sehen Sie eine Voraufzeichnung seines Vortrags mit dem Titel "Three Giants, Five Stars, Some Mistakes: Leonardo, Dürer, Kepler, and their Polyhedra" (auf Englisch).