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Consider the left-regular representation $\lambda : G \to B(L^2(G))$, $\lambda_g f(h) = f(g^{-1}h)$, for a locally compact group.

It is well-known that this is a unitary faithful and strongly-continuous representation, but is it also a homeomorphism onto its image $\lambda(G)$ (equipped with the strong-operator topology?

It would suffice to show that for any sequencenet $g_n$$g_\alpha$, convergence in the strong operator topology of $\lambda_{g_n}$$\lambda_{g_\alpha}$ to the identity $I_{L^2(G)}$ implies convergence of $g_n$$g_\alpha$ to the neutral element $e$ in $G$.

Consider the left-regular representation $\lambda : G \to B(L^2(G))$, $\lambda_g f(h) = f(g^{-1}h)$, for a locally compact group.

It is well-known that this is a unitary faithful and strongly-continuous representation, but is it also a homeomorphism onto its image $\lambda(G)$ (equipped with the strong-operator topology?

It would suffice to show that for any sequence $g_n$, convergence in the strong operator topology of $\lambda_{g_n}$ to the identity $I_{L^2(G)}$ implies convergence of $g_n$ to the neutral element $e$ in $G$.

Consider the left-regular representation $\lambda : G \to B(L^2(G))$, $\lambda_g f(h) = f(g^{-1}h)$, for a locally compact group.

It is well-known that this is a unitary faithful and strongly-continuous representation, but is it also a homeomorphism onto its image $\lambda(G)$ (equipped with the strong-operator topology?

It would suffice to show that for any net $g_\alpha$, convergence in the strong operator topology of $\lambda_{g_\alpha}$ to the identity $I_{L^2(G)}$ implies convergence of $g_\alpha$ to the neutral element $e$ in $G$.

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Lau
  • 769
  • 2
  • 10
Source Link
Lau
  • 769
  • 2
  • 10

Is the left-regular representation of a locally compact group a homeomorphism onto its image?

Consider the left-regular representation $\lambda : G \to B(L^2(G))$, $\lambda_g f(h) = f(g^{-1}h)$, for a locally compact group.

It is well-known that this is a unitary faithful and strongly-continuous representation, but is it also a homeomorphism onto its image $\lambda(G)$ (equipped with the strong-operator topology?

It would suffice to show that for any sequence $g_n$, convergence in the strong operator topology of $\lambda_{g_n}$ to the identity $I_{L^2(G)}$ implies convergence of $g_n$ to the neutral element $e$ in $G$.