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Tuesday, February 9, 2016

**Abstract:** The classical EHP sequence is a partial answer to the question of how far the unit map of the loop-suspension adjunction fails to be a weak equivalence. It can be used to move information from stable to unstable homotopy theory. I will explain why there is an EHP sequence in A1 algebraic topology, and what implications this has for the unstable A1 homotopy groups of spheres.