Every group is the outer automorphism group of an HNN-extension of a fixed triangle group
Alan Logan (University of Glasgow)
Wednesday 21st September, 2016 16:00-17:00 Maths 522
Fix i>8. In this talk we outline our proof that every countable group Q can be realised as Out(G_Q), where G_Q is an HNN-extension of the triangle group <a, b; a^i, b^i, c^i, abc>. The proof links aspherical presentations with free malnormal subgroups.