Notes on A 풯-algebras and extensions of A 핋-algebras by 풦
Hongliang Yao, Xiaochun Fang · Bulletin of the London Mathematical Society · 2010
H. Lin and H. Su classified A풯-algebras of real rank zero. An A풯-algebra often becomes an extension of an A핋-algebra by an AF-algebra. In this paper, we define a new invariant pi(A) of C*-algebra A by partial isometries and give a necessary condition on which a C*-algebra is an A풯-algebra. We demonstrate that there is an essential extension of an A핋-algebra with real rank zero by 풦 which is not an A풯-algebra.