Ricardo Brancas

PhD candidate in Computer Science · Lisbon

About

I'm a Computer Science PhD student in the CMU Portugal Affiliated PhD Program, advised by Vasco Manquinho at Instituto Superior Técnico and Ruben Martins at Carnegie Mellon University. My research helps programmers — and non-programmers — get through their daily work, by leaning on program synthesis and program repair. I'm also drawn to formal methods and compilers. Always happy to talk about any of it.

Selected Publications

2025

Combining Logic and Large Language Models for Assisted Debugging and Repair of ASP Programs — ICST 2025

Ricardo Brancas, Vasco Manquinho, Ruben Martins

Introduces FormHe, a tool that pairs logic-based techniques with LLMs to detect and correct issues in Answer Set Programming submissions.

PDF arXiv Code

2024

Towards Reliable SQL Synthesis: Fuzzing-Based Evaluation and Disambiguation — FASE 2024

Ricardo Brancas, Miguel Terra-Neves, Miguel Ventura, Vasco Manquinho, Ruben Martins

Introduces Cubes, a parallel SQL synthesizer using input/output examples and a user-guided disambiguation process — up to 60% accuracy with super-linear speedups on multicore.

PDF arXiv (extended) Code

2023

On Repairing Natural Language to SQL Queries — arXiv

Aidan Z.H. Yang, Ricardo Brancas, Pedro Esteves, Sofia Aparicio, Joao Pedro Nadkarni, Miguel Terra-Neves, Vasco Manquinho, Ruben Martins

PDF arXiv

Projects

ProFix

An ongoing project to support students taking Logic Programming courses. The first phase surveys students to map the most common difficulties when learning Prolog.

FormHe

A tool that helps users find and fix problems in ASP programs. A fault-localization module identifies which statements are off based on an exemplifying query; a repair module then suggests fixes via program synthesis.

Cubes

A parallel program synthesizer for SQL queries from input/output examples. Cubes extends sequential query synthesizers with new pruning techniques and a divide-and-conquer split of the search space.