The inverse problem for primitive ideal spaces

TL;DR

This paper characterizes primitive ideal spaces of separable nuclear C*-algebras topologically, constructs a related Hilbert bimodule, and links the primitive ideal space to Cuntz--Pimsner algebras with a focus on topological and algebraic properties.

Contribution

It provides a topological characterization of primitive ideal spaces and constructs a Cuntz--Pimsner algebra with a primitive ideal space isomorphic to a given space.

Findings

Primitive ideal spaces are point-complete second countable T0-spaces.

Constructed a Hilbert bimodule over C_0(X) with specific properties.

Established KK(X;.,.)-equivalence to C_0(P) and functoriality via tensoring with O_2.

Abstract

A pure topological characterization of primitive ideal spaces of separable nuclear C*-algebras is given. We show that a $T_0$-space $X$ is a primitive ideal space of a separable nuclear C*-algebra $A$ if and only if $X$ is point-complete second countable, and there is a continuous pseudo-open and pseudo-epimorphic map from a locally compact Polish space $P$ into $X$. We use this pseudo-open map to construct a Hilbert bi-module $\mathcal{H}$ over $C_0(X)$ such that $X$ is isomorphic to the primitive ideal space of the Cuntz--Pimsner algebra $\mathcal{O}_\mathcal{H}$ generated by $\mathcal{H}$. Moreover, our $\mathcal{O}_\mathcal{H}$ is $KK(X;.,.)$-equivalent to $C_0(P)$ (with the action of $X$ on $C_0(P)$ given be the natural map from $\mathbb{O}(X)$ into $\mathbb{O}(P)$, which is isomorphic to the ideal lattice of $C_0(P)$. Our construction becomes almost functorial in $X$ if we tensor $\mathcal{O}_\mathcal{H}$ with the Cuntz algebra $\mathcal{O}_2$.