Joris Koefler (MPI MiS Leipzig) - The Infinituhedron

The amplituhedron is a semi-algebraic set given as the image of the positive Grassmannian under a linear map subject to a choice of additional parameters. We define the Infinituhedron as the limit of amplituhedra by sending one of the parameters to infinity. We derive its algebraic boundary in terms of Chow varieties and explain its geometric interpretation from the point of view of Positive Geometry in terms of secants of the rational normal curve. This discussion shows that the Infinituhedron is a positive geometry with a unique differential form. Joint work with Rainer Sinn.