Central charges and RG flow of strongly-coupled N=2 theory

We calculate the central charges a, c and k_G of a large class of four-dimensional N=2 superconformal field theories arising from compactifying the six-dimensional N=(2,0) theory on a Riemann surface with regular and irregular punctures. We also study the renormalization group flows between the general Argyres-Douglas theories, which all agree with the a-theorem.