Published in the conference proceedings of Banach Algebras 2009, as
Banach Center Publ. 91 (2010), 105--121.
Preprint version available at
[ Math Reviews | Zentralblatt (summary) ]
We revisit the old result that biflat Banach algebras have the same cyclic cohomology as C, and obtain a quantitative variant (which is needed in forthcoming joint work of the author). Our approach does not rely on the Connes-Tsygan exact sequence, but is motivated strongly by its construction as found in [Connes,1985] and [Helemskii,1992].
The result here is used in work with Gourdeau and White (Proc. Royal Soc. Edinburgh, Sect. A, 2012; see this link).
The MR does not appear to get what the point of the paper is, even though I tried to make this explicit in the introduction. I will try to write something here when time permits.