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Marc Palm
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Consider a locally compact group $G$ and a cocompact subgroup $H$, is it known that the induction of an irreducible representation $\pi$ of $H$ to $G$ decomposes discretely into a direct sum of irreducible with finite multiplicity?

I know that this is true, for $\pi$ trivial and $H$ unimodular (=> G unimodular). Is unimodularity here necessary?

Please provide either a counterexample or a reference, that this does or does not hold in general.

Consider a locally compact group $G$ and a cocompact subgroup $H$, is it known that the induction of an irreducible representation $\pi$ of $H$ to $G$ decomposes discretely into a direct sum of irreducible with finite multiplicity?

I know that this is true, for $\pi$ trivial and $H$ unimodular (=> G unimodular).

Consider a locally compact group $G$ and a cocompact subgroup $H$, is it known that the induction of an irreducible representation $\pi$ of $H$ to $G$ decomposes discretely into a direct sum of irreducible with finite multiplicity?

I know that this is true, for $\pi$ trivial and $H$ unimodular (=> G unimodular). Is unimodularity here necessary?

Please provide either a counterexample or a reference, that this does or does not hold in general.

Source Link
Marc Palm
  • 11.2k
  • 2
  • 35
  • 92

Inducing from cocompact subgroups

Consider a locally compact group $G$ and a cocompact subgroup $H$, is it known that the induction of an irreducible representation $\pi$ of $H$ to $G$ decomposes discretely into a direct sum of irreducible with finite multiplicity?

I know that this is true, for $\pi$ trivial and $H$ unimodular (=> G unimodular).