부산대학교 도서관

We examine the structure of two possible candidates of isometry groups for the spectral triples on $AF$-algebras introduced by Christensen and Ivan. In particular, we completely determine the isometry group introduced by Park, and observe that these groups coincide in the case of the Cantor set. We also show that the construction of spectral triples on crossed products given by Hawkins, Skalski, White and Zacharias, is suitable for the purpose of lifting isometries.
Comment: 17 pages. We corrected the formula for the group structure of isometries in the case of the Cantor set (Proposition 3.12 and Postface). Accepted for publication in J. Noncommut. Geom