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Let $M$ be an oriented Riemannian manifold of dimension $n$. For any $\omega \in \Omega^k(M)$, we define the Hodge star operator $\star$ of a $\omega$ as the unique $n-k$ form $\star\omega$ that satisfies $$\omega \wedge (\star\omega) = \langle \omega, \omega \rangle dVol.$$

How is this operation extended to forms that now take values in a vector space $V$?

Similar to this post, I am interested in this because of its applications to Yang-Mills theory where we have $F \wedge \star F$ and where $F$ is a 2-form with values in a Lie algebra $\mathfrak{g}$. The accepted answer explains how to wedge two vector-valued forms, but I am interested in the Hodge star of two vector-valued forms.

Can this only be done locally in the sense that if $V$ has dimension $m$, then $$\omega = \sum_{i=1}^m \omega_i \otimes e_i$$ then $$\star\omega = \sum_{i=1}^m (\star\omega_i) \otimes e_i$$ where $\omega_i$ is a real-valued $k$-form and $\{e_i\}$ is a basis for $V$?

CBBAM
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  • Don't you want $\omega\wedge\star\omega$ to still be be a scalar-valued form? How're you going to arrange that? This is not inventing the wheel. You can find such material in any decent complex manifolds text. Try Wells, Griffiths and Harris, or Huybrechts. – Ted Shifrin Nov 14 '23 at 04:18
  • I thought since $\omega$ and $\star \omega$ are both vector-valued that we'd want their wedge product to also be vector valued? Thank you very much for the resources, I am self-taught so it's been tough finding good texts. Do you know of any texts that go over the Hodge star operator for vector valued forms for spaces more general than $\mathbb{C}$? – CBBAM Nov 14 '23 at 04:30
  • Complex geometry is full of vector-bundle valued forms. These texts all treat that and the Hodge star in that setting. I would recommend studying the text(s) thoroughly, rather than trying to get a piecemeal understanding from questions here. – Ted Shifrin Nov 14 '23 at 05:05
  • @TedShifrin I will do that, thank you for your help! – CBBAM Nov 14 '23 at 05:35

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