During the 2021-22 academic year, the CMSA will be hosting a seminar on Combinatorics, Physics and Probability, organized by Matteo Parisi and Michael Simkin. This seminar will take place on **Tuesdays** at **9:30am â€“ 10:30am (Boston time)**. The meetings will take place virtually on Zoom. To learn how to attend, please fill out this form, or contact the organizers Matteo (mparisi@cmsa.fas.harvard.edu) and Michael (msimkin@cmsa.fas.harvard.edu).

The schedule below will be updated as talks are confirmed.

Date | Speaker | Title/Abstract |

9/21/2021 | Nima Arkani-Hamed IAS (Institute for Advanced Study), School of Natural Sciences | Title: Surfacehedra and the Binary Positive Geometry of Particle and “String” Amplitudes |

9/28/2021 | Melissa Sherman-Bennett University of Michigan, Department of Mathematics | Title: The hypersimplex and the m=2 amplituhedronAbstract: I’ll discuss a curious correspondence between the m=2 amplituhedron, a 2k-dimensional subset of Gr(k, k+2), and the hypersimplex, an (n-1)-dimensional polytope in R^n. The amplituhedron and hypersimplex are both images of the totally nonnegative Grassmannian under some map (the amplituhedron map and the moment map, respectively), but are different dimensions and live in very different ambient spaces. I’ll talk about joint work with Matteo Parisi and Lauren Williams in which we give a bijection between decompositions of the amplituhedron and decompositions of the hypersimplex (originally conjectured by Lukowski–Parisi–Williams). Along the way, we prove the sign-flip description of the m=2 amplituhedron conjectured by Arkani-Hamed–Thomas–Trnka and give a new decomposition of the m=2 amplituhedron into Eulerian-number-many chambers (inspired by an analogous hypersimplex decomposition). |

10/5/2021 | Daniel Cizma, Hebrew University | |

10/12/2021 | Lisa Sauermann, MIT | |

10/19/2021 | Pavel Galashin UCLA, Department of Mathematics | |

10/26/2021 | Candy Bowtell Oxford, Mathematical Institute | |

11/2/2021 | Jacob Bourjaily Penn State University, Department of Physics | |

11/9/2021 | Steven Karp Universite du Quebec a Montreal, LaCIM (Laboratoire de combinatoire et d’informatique mathÃ©matique) | |

11/16/2021 | ||

11/23/2021 | Lutz Warnke Georgia Tech | |

11/30/2021 | ||

12/7/2021 | ||

12/14/2021 | ||

12/21/2021 |