For sphere maps into a loop space or a group-like homotopy-associative space, take their pointwise commutator. It is trivial on the wedge sum of the two sphere factors, so descends to their smash product and defines . This product obeys graded antisymmetry and the graded Jacobi identity. Suspension-loop adjunction identifies it with the sign-adjusted Whitehead product. Under the Hurewicz homomorphism it becomes the graded commutator of the Pontryagin product.
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