Mobius functions for real hyperplane arrangements.
Time: 11:00 -- Location: Salle Philippe Flajolet du LIX
We discuss the beginnings of a theory of noncommutative Mobius functions and its connections to the structure of the algebra of faces of a hyperplane arrangement. It is to be seen as a generalization of the theory of Mobius functions for lattices, developed by Rota and his school in the 70's. Joint work with Swapneel Mahajan.