On Wiener-Hopf operators over linearly ordered diskrete Abelian groups

Let $X$ denotes a discrete linearly ordered Abelian group, and let $X_+$ be the positive cone in $X$. In this note we compute the Fredholm index and study spectral properties of Wiener-Hopf operators $W_kg=1_{X_+}(k\ast g)$, $k\in l_2(X_+)$ in the space $l_2(X_+)$ in terms of their symbols $\check k$ where $\check k$ stands for the inverse Fourier transform of $k$.