EMNLP2025

Hierarchical Bracketing Encodings Work for Dependency Graphs

Ana Ezquerro, Carlos Gómez-Rodríguez, David Vilares

Abstract

We revisit hierarchical bracketing encodings from a practical perspective in the context of dependency graph parsing. The approach encodes graphs as sequences, enabling linear-time parsing with nn tagging actions, and still representing reentrancies, cycles, and empty nodes. Compared to existing graph linearizations, this representation substantially reduces the label space while preserving structural information. We evaluate it on a multilingual and multi-formalism benchmark, showing competitive results and consistent improvements over other methods in exact match accuracy.