Dear All, We are delighted to present the MaPSS Seminar topic of Monday 29/05; please see the abstract below. **This Semester the Seminar will always run on Monday, at 5:00pm in 535A** Following the talk, there will be pizza on offer. Speaker: Giulia Codenotti (Freie University, Berlin) Title: Triangulated spheres and Pachner moves Abstract: In the world of discrete geometry-somewhere between combinatorics and geometry- Pachner moves (or bistellar flips) are an important tool to "build up" complex triangulations from more simple ones while preserving topological properties. I will give an introduction of basic objects in discrete geometry such as polytopes and simplicial complexes and show with examples how Pachner moves can help both to devise new questions and to answer others, spanning topics from combinatorics to topology. Supervisors, please encourage your students to attend. Thanks, MaPSS Organisers