Reductive cohomology associated with vertex algebras

We review the notion of the reduction cohomology of vertex algebras. The algebraic conditions leading to the chain property for complexes of vertex operator algebra n-point functions (with their convergence assumed) with a coboundary operator defined through reduction formulas are studied. Algebraic, geometrical, and cohomological meanings of reduction formulas and chain condition are clarified. The reduction cohomology for vertex operator algebras associated to Jacobi forms is computed. A counterpart of the Bott-Segal theorem for Riemann surfaces in terms of the reductions cohomology is proven.