Seminar series
Date
Wed, 29 Oct 2014
12:30
12:30
Location
N3.12
Speaker
Giles Gardam
Organisation
Oxford University
Stallings' folding technique lets us factor a map of graphs as a sequence of "folds" (edge identifications) followed by an immersion. We will show how this technique gives an algorithm to express a free-group automorphism as the product of Whitehead automorphisms (and hence Nielsen transformations), as well as proving finite generation for some subgroups of the automorphism group of a free group.