  Through coarse-graining, tensor network representations of a two-dimensional
critical lattice model flow to a universal four-leg tensor, corresponding to a
conformal field theory (CFT) fixed-point. We computed explicit elements of the
critical fixed-point tensor, which we identify as the CFT four-point function.
This allows us to directly extract the operator product expansion coefficients
of the CFT from these tensor elements. Combined with the scaling dimensions
obtained from the transfer matrix, we determine the complete set of the CFT
data from the fixed-point tensor for any critical unitary lattice model.
