Abstract
We show that cyclic cohomology of an algebraA is obtained from traces with suitable domains on the algebraqA of the second author. WhenA is aC* algebra so isqA and the notion of positive trace makes sense. We hence get a notion of positivity for cyclic cocycles. We prove that a positive trace onqA defines a type I or II Fredholm module onA.
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Communicated by A. Jaffe
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Connes, A., Cuntz, J. Quasi homomorphismes, cohomologie cyclique et positivité. Commun.Math. Phys. 114, 515–526 (1988). https://doi.org/10.1007/BF01242141
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DOI: https://doi.org/10.1007/BF01242141