valid only for the distributions with a support $0\le x\le \zeta$ [@RadPRD56].

NLO coefficient functions for DVCS.
===================================

In the previous section we have dealt so far with the LO analysis and have seen that the tree conformal operators (\[treeCO\]) diagonalize the anomalous dimension matrix. As we have mentioned in the Introduction, this property breaks down in the NLO in the ${\overline{\rm MS}}$ scheme even in the theory with $\beta = 0$. However, the conformal constraints (\[conf-constr-KD-1\]) and (\[conf-constr-KD-2\]) ensure the existence of the CS scheme, in which the conformal covariance is restored in the conformal limit of the theory to any order of perturbation theory. In this scheme the OPE in terms of the conformally covariant operators [@FGG73] holds true in the interacting theory and provides powerful restrictions on the corresponding Wilson coefficients and can be served, for instance, as a tool for the calculation of the scattering amplitude of two-photon processes in the generalized Bjorken region. To compare the predictions with the calculations performed in the ${\overline{\rm MS}}$ scheme, the following transformation for the operators is necessary $$\begin{aligned}
\label{transformation}
{\cal O}_{jl}=\sum_{j'=0}^{j} B_{jj'} \widetilde {\cal O}_{j'l}.\end{aligned}$$ In the CS scheme the operators $\widetilde O_{jl}$ in different conformal towers do 