He changed supervisors and began working on algebraic topology with Shaun Wylie. However, he was most strongly influenced by Henry Whitehead, who led the foremost British school of algebraic topology.
Siya ay nagbago supervisors at nagsimulang gumawa sa algebraic topology sa Shaun Wylie. Gayunman, siya ang pinaka Matindi ang naiimpluwensyahan ng Henry Whitehead, na humantong sa kauna-unahan British paaralan ng algebraic topology.