Math and Magic
Time: September 19, 2024 - 4:00-5:00pm
Location: IES 111
The presentation will be about half and hour, and there will be some refreshments and discussion in the room immediately afterwards.
Speaker: Sergio Alejandro Fernandez de Soto Guerrero (Graz University of Technology)
Title: MathMagic: A positroidal action over a deck of cards
Abstract: Positroids are a subclass of matroids born in the study of the non-negative Grassmanian by Postnikov in 2006. Since then, there have been a plethora of combinatorial objects indexing positroids, two of these being the families of decorated and bicolored permutations, which are generalizations of classical permutations. These two families can be used to study properties of positroids, and as a byproduct we end up with useful ways to describe a group action on a deck of cards. In this context, we give a definition of invariants under this group action allowing us, as an application, to develop new magic tricks with unusual ways of shuffling cards.