On resummation of the irregular conformal block

We discuss the resummation procedure of the superpotential in 4d $\mathcal{N}=2$ SYM theory without matter from the point of view of 2d Liouville conformal field theory, utilizing the AGT correspondence. We identify contributions of different descendants of the intermediate state, defining a conformal block in CFT, to the superpotential and answer the question, which descendants are responsible for the appearance of the branch cuts in the superpotential.