Department of Mathematics, University of Mississippi, University, Mississippi 38677 ; Department of Mathematics, Texas A&M University, College Station, Texas 77843
Abstract:
We investigate the cohomology of non-self-adjoint algebras using virtual diagonals and their higher-dimensional generalizations. We show that infinite dimensional nest algebras always have non-zero second cohomology by showing that they cannot possess 2-virtual diagonals. In the case of the upper triangular atomic nest algebra we exhibit concrete modules for non-vanishing cohomology.