Let $(M,g)$ be a complete oriented Riemannian manifold. If $Ric ≥ 0$ on $M$, then any harmonic 1-form $\alpha$ is parallel i.e $x\to |\alpha|^2_{g,x}$ constant?
1 Answer
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What about the plane? It has harmonic 1-forms, for example: real parts of holomorphic 1-forms.