A note on twisted crossed products and spectral triples

Starting with a spectral triple on unital C⁎-algebra A an action of discrete group G, if the is uniformly bounded (in Lipschitz sense) reduced crossed product A⋊rG constructed in [23]. The main instrument Kasparov external product. We note that this construction still works for twisted products when appropriate sense. Under suitable assumptions we discuss some basic properties resulting triples: summability and regularity. Noncommutative coverings finite abelian structure are among most basic, interesting, examples products; describe their features.