This chapter deals with computation trees over an arbitrary structure. It is devoted to the comparative analysis of three parameters of problems with n input variables over this structure: the complexity of a problem description, the minimum complexity of a computation tree solving this problem deterministically, and the minimum complexity of a computation tree solving this problem nondeterministically. Rough classification of relationships among these parameters is considered and all possible seven types of these relations are enumerated. The changes of relation types with the growth of the number n of input variables are studied.