In this answer here t.b. writes that $\ell^1(\mathbb Z)$ would then have to be isomorphic to a space of the form $C(K)$ with $K$ compact (metrizable and infinite).
What is the result they are referring to?
In this answer here t.b. writes that $\ell^1(\mathbb Z)$ would then have to be isomorphic to a space of the form $C(K)$ with $K$ compact (metrizable and infinite).
What is the result they are referring to?
Every commutative unital $C^*$ algebra is of the form $C(K)$. This follows from the Gelfand theory. For more references, see here.