  In a recent paper (arXiv:0906.3219) the representation of Nekrasov partition
function in terms of nontrivial two-dimensional conformal field theory has been
suggested. For non-vanishing value of the deformation parameter
\epsilon=\epsilon_1+\epsilon_2 the instanton partition function is identified
with a conformal block of Liouville theory with the central charge c = 1+
6\epsilon^2/\epsilon_1\epsilon_2. If reversed, this observation means that the
universal part of conformal blocks, which is the same for all two-dimensional
conformal theories with non-degenerate Virasoro representations, possesses a
non-trivial decomposition into sum over sets of the Young diagrams, different
from the natural decomposition studied in conformal field theory. We provide
some details about this intriguing new development in the simplest case of the
four-point correlation functions.
