From Fragmentation to Concentration of Claims in Brazilian Law<br>—Investigating the Limitation on the Fragmentation of the Substantive Legal Situation into Different Proceedings

The article investigates the so-called fragmentation of claims arising from the same substantive legal situation into multiple lawsuits. Based on the observation that the Brazilian civil procedural system does not define the minimum content of a claim nor impose the joinder of related claims, the paper proposes a dogmatic reconstruction of the duty of claim concentration. After demonstrating the impacts of fragmentation on the efficiency, legal certainty, and rationality of the proceedings, the study compares two possible solutions: the approach based on abuse of rights, deemed insufficient, and the definition of the subject matter of the proceedings based on the substantive legal situation. It concludes that there is a general rule of concentration, with justified exceptions, and that new lawsuits may be inadmissible when the fragmentation is unjustified.