Civil procedural law is a system of legal rules governing the judicial enforcement of rights arising from certain civil law relationships. When several procedural subjects appear in a party's role in a lawsuit, then we speak of adversary, and it is characterized by a plurality of subjects, holders of rights and obligations. Rivalry is always permitted when it is expedient to hold a joint discussion and make a joint decision, which is primarily based on reasons of the economy of the procedure and the realization of the principle of legal certainty. As a rule, the cumulation of procedural subjects is accompanied by the cumulation of claims, and as many procedural relationships are formed as there are claims. demands. Rivalry is, as a rule, optional, and the result of the prosecutor's procedural disposition, i.e. it depends on his will. Rivalry can exceptionally be mandatory, in which case it is necessary rivalry. Regarding the general assumptions for the establishment of litigation, the existence of common procedural rules regarding the jurisdiction of the court, party and litigation capacity, representation, absence of procedural obstacles is necessary.