University of Oregon: Department of Mathematics

Topology Seminar: Michael Dyer (University of Oregon), Constructing elements of the second homotopy group from subgroups of the fundamental group.

Let X be a two-complex and G be its fundamental group. Let A be a non-trivial subgroup of G. The talk will describe a simple but delicate process for using A to define non-trivial elements of the second homotopy group of X.