Title: On Representations of Fredholm and Semi-Fredholm Spectra of Multi-Toeplitz Operators with Symbols inH∞+C
Abstract: In this paper, we give the representations of Fredholm and semi-Fredholm spectra of multi-Toeplitz operators with symbols inH∞+C, and prove that, for ϕ1,…,ϕn∈H∞+C(n≥2), if (Tϕ1,…,Tϕn) is Fredholm, then ind(Tϕ1,…,Tϕn)=0, in contrast with the case of one operator.