Financial support through the following projects:

UID/MAT/00297/2019
UID/MAT/00297/2013
PEst-OE/MAT/UI0297/2014
PEst-OE/MAT/UI0297/2011

# A C*-algebra of singular integral operators with shifts and PQC coefficients

Analisys Seminar

A Fredholm symbol calculus is constructed for the C*-algebra generated on the space $L^2$ over the unit circle by the operators of multiplication by  piecewise quasicontinuous functions, by the Cauchy singular integral operator and by the unitary shift operators related to a group $G$ of orientation-preserving diffeomorphists of the unit circle onto itself that have the same finite set of fixed points for all $g\in G\setminus\{e\}$. A Fredholm criterion for the operators in this C*-algebra is then established in