  The role of various symmetries in the evaluation of splitting functions and
coefficient functions is discussed. The scale invariance in hard processes is
known to be a guiding tool to understand the dynamics. We discuss the
constraints on splitting functions coming from various symmetries such as
scale, conformal and supersymmetry. We also discuss the Drell-Levy-Yan relation
among splitting and coefficient functions in various schemes. The relations
coming from conformal symmetry are also presented.
