Homotopy of vector states

Andruchow, Esteban; Varela, Alejandro
Bibliographical reference

eprint arXiv:math/0008144

Advertised on:
8
2000
Number of authors
2
IAC number of authors
0
Citations
0
Refereed citations
0
Description
Let $B$ be a C$^*$-algebra and $X$ a C$^*$ Hilbert $B$-module. If $pin B$ is a projection, denote by $S_p ={xin X : < x,x> =p}$, the $p$-sphere of $X$. For $phi$ a state of $B$ with support $p$ in $B$ and $xin S_p$, consider the state $phi_x$ of $L_B(X)$ given by $phi_x(t)= phi(< x,t(x)>)$. In this paper we study certain sets associated to these states, and examine their topologic properties. As an application of these techniques, we prove that the space of states of the hyperfinite II$_1$ factor $R_0$, with support equivalent to a given projection $pin R_0$, regarded with the norm topology (of the conjugate space of $R_0$), has trivial homotopy groups of all orders. The same holds for the space $$ S_p(R_0)={vin R_0:v^*v=p}subset R_0 $$ of partial isometries with initial space $p$, regarded with the ultraweak topology.