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MiS Preprint
24/2000
S^1-invariant harmonic maps from S^3 to S^2
Guofang Wang
Abstract
In this note, we show that a homotopy class of [S³, S²] admits an S¹-invariant harmonic map if and only if its Hopf invariant is ±k² for some integer k, where S³ is the unit 3-sphere and S² is a 2-sphere with an arbitrary metric.
