Preface Wolfgang Metzler and Stephan Rosebrock; List of contributors; 1. A survey of recent progress on some problems in 2-dimensional topology Jens Harlander; Appendix: geometric realization for algebraic 2-complexes with finite fundamental group F. Rudolf Beyl and Jens Harlander; 2. Further results concerning the Andrews–Curtis conjecture and its generalizations Cynthia Hog-Angeloni and Wolfgang Metzler; 3. Aspects of TQFT and computational algebra Holger Kaden and Simon King; 4. Labelled oriented trees and the Whitehead conjecture Stephan Rosebrock and Jens Harlander; 5. 2-complexes and 3-manifolds Janina Glock, Cynthia Hog-Angeloni and Sergei Matveev; 6. The relation gap problem Jens Harlander; 7. On the relation gap problem for free products Cynthia Hog-Angeloni and Wolfgang Metzler; References; Index; Erratum.