Formal Methods

Large Language Models Are Not (Yet) Robust in Understanding Code Against Semantics-Preserving Mutations @ EPIA 2026 featured image

Large Language Models Are Not (Yet) Robust in Understanding Code Against Semantics-Preserving Mutations @ EPIA 2026

In this talk, we will present an empirical study investigating whether state-of-the-art Large Language Models (LLMs) can genuinely reason about Python programs or are simply …

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Pedro Orvalho
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Solving MaxSAT Problems from Natural Language Descriptions with LLMs and PySAT @ LLM-Solve @ FLoC 2026 featured image

Solving MaxSAT Problems from Natural Language Descriptions with LLMs and PySAT @ LLM-Solve @ FLoC 2026

In this talk, we will present a framework for solving MaxSAT problems expressed in natural language by combining large language models with the PySAT toolkit. We will show how LLMs …

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Pedro Orvalho
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📄🤖 2 Papers accepted @ EPIA 2026!! 🎉🎉 featured image

📄🤖 2 Papers accepted @ EPIA 2026!! 🎉🎉

Excited to share that two of our papers have been accepted at EPIA 2026, covering the robustness of LLMs for code understanding and neuro-symbolic feedback for Vision-Language …

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Pedro Orvalho
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Large Language Models Are Not (Yet) Robust in Understanding Code Against Semantics-Preserving Mutations featured image

Large Language Models Are Not (Yet) Robust in Understanding Code Against Semantics-Preserving Mutations

In this paper we assess whether SOTA LLMs can reason about Python programs or are simply guessing. We apply five semantics-preserving code mutations, which maintain program …

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Pedro Orvalho
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📄📄📄 3 Papers accepted @ FLoC 2026!! 🎉🎉🎉 featured image

📄📄📄 3 Papers accepted @ FLoC 2026!! 🎉🎉🎉

Excited to share that three of our papers have been accepted at FLoC 2026, covering automated feedback for Prolog education, data-driven mutation testing for Prolog, and …

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Pedro Orvalho
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Solving MaxSAT Problems from Natural Language Descriptions with LLMs and PySAT featured image

Solving MaxSAT Problems from Natural Language Descriptions with LLMs and PySAT

In this paper, we study a neuro-symbolic approach in which an LLM translates a natural language description of an optimisation problem into executable Python code using PySAT. The …

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Pedro Orvalho
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From Brittle LLM Code Reasoning to MaxSAT-Based Verified Repairs @ UCL featured image

From Brittle LLM Code Reasoning to MaxSAT-Based Verified Repairs @ UCL

In this talk, we examine the limitations of Large Language Models (LLMs) in semantic code reasoning, showing that their predictions may change under semantics-preserving code …

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Pedro Orvalho
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Towards Assessing and Repairing LLM-Generated Code via Model Checking and MaxSAT-Based Fault Localisation @ Dagstuhl 2026 featured image

Towards Assessing and Repairing LLM-Generated Code via Model Checking and MaxSAT-Based Fault Localisation @ Dagstuhl 2026

LLMs for code often lack true semantic understanding, evidenced by their instability under semantics-preserving transformations, and we address this by integrating formal methods …

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Pedro Orvalho
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Sherlock4Py featured image

Sherlock4Py

🔎🐛 Sherlock4Py 🐍 MaxSAT-Based Misbehaviour Verification and Localisation Framework for Python Sherlock4Py is a research project investigating how formal reasoning and Large …

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Pedro Orvalho
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PyVeritas: On Verifying Python via LLM-Based Transpilation and Bounded Model Checking for C @ P-AI-FM@AAAI 2026 featured image

PyVeritas: On Verifying Python via LLM-Based Transpilation and Bounded Model Checking for C @ P-AI-FM@AAAI 2026

In this talk I will present PyVeritas, a novel framework that leverages Large Language Models (LLMs) for high-level transpilation from Python to C, followed by bounded model …

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Pedro Orvalho
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PyVeritas: On Verifying Python via LLM-Based Transpilation and Bounded Model Checking for C featured image

PyVeritas: On Verifying Python via LLM-Based Transpilation and Bounded Model Checking for C

In this paper, we propose PyVeritas, a novel framework that leverages Large Language Models (LLMs) for high-level transpilation from Python to C, followed by bounded model checking …

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Pedro Orvalho
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📄 Paper accepted @ the Post-AI Formal Methods Workshop @ AAAI 2026! 🎉 featured image

📄 Paper accepted @ the Post-AI Formal Methods Workshop @ AAAI 2026! 🎉

I’m excited to share that our paper on PyVeritas has been accepted to the P-AI-FM-26 Workshop @ AAAI 2026! 📄

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Pedro Orvalho
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Neuro-Symbolic AI for Reliable Reasoning featured image

Neuro-Symbolic AI for Reliable Reasoning

Modern foundation models, including Large Language Models (LLMs) and Vision-Language Models (VLMs), have remarkable capabilities for understanding natural language, code, and …

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Pedro Orvalho
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MENTOR: Automated Feedback for Introductory Programming Exercises featured image

MENTOR: Automated Feedback for Introductory Programming Exercises

This PhD thesis presents MENTOR, a semantic automated program repair (APR) framework designed to provide Automated Feedback for Introductory Programming Exercises.

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Pedro Orvalho
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Counterexample Guided Program Repair Using Zero-Shot Learning and MaxSAT-based Fault Localization featured image

Counterexample Guided Program Repair Using Zero-Shot Learning and MaxSAT-based Fault Localization

In this paper, we propose a novel approach that combines the strengths of both FM-based fault localization and LLMs, via zero-shot learning, to enhance APR for IPAs. Our method …

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Pedro Orvalho
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Model-Based Diagnosis for Software featured image

Model-Based Diagnosis for Software

Localising system faults has long been recognised as one of the most time-consuming and costly tasks in software engineering. Given a buggy system, fault localisation (FL) refers …

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Pedro Orvalho
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