Guilherme Lima


2024

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Deductive Verification of LLM Generated SPARQL Queries
Alexandre Rademaker | Guilherme Lima | Sandro Rama Fiorini | Viviane Torres da Silva
Proceedings of the Workshop on Deep Learning and Linked Data (DLnLD) @ LREC-COLING 2024

Considering the increasing applications of Large Language Models (LLMs) to many natural language tasks, this paper presents preliminary findings on developing a verification component for detecting hallucinations of an LLM that produces SPARQL queries from natural language questions. We suggest a logic-based deductive verification of the generated SPARQL query by checking if the original NL question’s deep semantic representation entails the SPARQL’s semantic representation.

2023

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Extracting higher-order logic formulas from English sentences
Alexandre Rademaker | Guilherme Lima | Renato Cerqueira
Proceedings of the 6th International Conference on Natural Language and Speech Processing (ICNLSP 2023)

2022

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SYGMA: A System for Generalizable and Modular Question Answering Over Knowledge Bases
Sumit Neelam | Udit Sharma | Hima Karanam | Shajith Ikbal | Pavan Kapanipathi | Ibrahim Abdelaziz | Nandana Mihindukulasooriya | Young-Suk Lee | Santosh Srivastava | Cezar Pendus | Saswati Dana | Dinesh Garg | Achille Fokoue | G P Shrivatsa Bhargav | Dinesh Khandelwal | Srinivas Ravishankar | Sairam Gurajada | Maria Chang | Rosario Uceda-Sosa | Salim Roukos | Alexander Gray | Guilherme Lima | Ryan Riegel | Francois Luus | L V Subramaniam
Findings of the Association for Computational Linguistics: EMNLP 2022

Knowledge Base Question Answering (KBQA) involving complex reasoning is emerging as an important research direction. However, most KBQA systems struggle with generalizability, particularly on two dimensions: (a) across multiple knowledge bases, where existing KBQA approaches are typically tuned to a single knowledge base, and (b) across multiple reasoning types, where majority of datasets and systems have primarily focused on multi-hop reasoning. In this paper, we present SYGMA, a modular KBQA approach developed with goal of generalization across multiple knowledge bases and multiple reasoning types. To facilitate this, SYGMA is designed as two high level modules: 1) KB-agnostic question understanding module that remain common across KBs, and generates logic representation of the question with high level reasoning constructs that are extensible, and 2) KB-specific question mapping and answering module to address the KB-specific aspects of the answer extraction. We evaluated SYGMA on multiple datasets belonging to distinct knowledge bases (DBpedia and Wikidata) and distinct reasoning types (multi-hop and temporal). State-of-the-art or competitive performances achieved on those datasets demonstrate its generalization capability.