Homogeneous components in the moduli space of sheaves and Virasoro characters

A. Buryak, B. L. Feigin

The moduli space $\mathcal{M}(r,n)$ of framed torsion free sheaves on the projective plane with rank $r$ and second Chern class equal to $n$ has the natural action of the $(r+2)$-di…