Time: 9h00, Thursday, October 4, 2018
Location: Room 302, Building A5, Institute of Mathematics
Abstract: Plus-one generated arrangements are introduced recently by Takuro Abe through the inspiration of Dimca-Sticlaru's notion of nearly free line and plane arrangements. Terao's deletion theorem concerns the freeness of an arrangement obtained by deleting a hyperplane from a free arrangement. We are going to discuss two results in the recent works of Abe. Firstly, the deleted arrangement is either free or strictly plus-one generated. Secondly, the Terao's deletion theorem is combinatorial i.e. whether the deleted arrangement is free depends only on the intersection lattice.