User:Stefan.fredenhagen/sandbox

OPEs
$$T(z) T(w) \sim \frac{c/2}{(z-w)^4}+ \frac{2T(w)}{(z-w)^2} + \frac{\partial T(w)}{z-w}$$
 * OPE of energy-momentum tensor

$$T(z) \phi_\Delta(w) \sim \frac{\Delta \phi_\Delta(w)}{(z-w)^2} + \frac{\partial \phi_\Delta(w)}{z-w}$$
 * OPE of energy-momentum tensor with a primary field of weight $$\Delta$$

$$J^a(z) J^b(w) \sim \frac{k\, \kappa^{ab}}{(z-w)^2} + \frac{i\,f^{ab}{}_c \, J^c(w)}{z-w} $$
 * OPE of currents