The completely bounded approximation property for discrete crossed products A. SinclairR. Smith 46L0546L40Fourier algebraHaagerup constants Indiana University Mathematics Journal 1997 text pdf 10.1512/iumj.1997.46.1428 10.1512/iumj.1997.46.1428 en Indiana Univ. Math. J. 46 (1997) 1311 - 1322 state-of-the-art mathematics http://iumj.org/access/