@inproceedings{lopez-ponce-etal-2026-gil,
    title = "{GIL}-{Z}aragoza at {S}em{E}val 2026 Task 11: Comparing Classification, Autoformalization, and Ontologies for Formal Reasoning Capabilities",
    author = "Lopez-Ponce, Francisco  and
      Pitarch, Lucia  and
      Saavedra Mart{\'i}nez, Iv{\'a}n  and
      Huitzil, Ignacio  and
      Ojeda Trueba, Sergio  and
      Bobillo, Fernando  and
      Bel-Enguix, Gemma",
    editor = "Kochmar, Ekaterina  and
      Ghosh, Debanjan  and
      North, Kai  and
      Komachi, Mamoru",
    booktitle = "Proceedings of the 20th {I}nternational {W}orkshop on {S}emantic {E}valuation (2026)",
    month = jul,
    year = "2026",
    address = "San Diego, California, USA",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.308/",
    pages = "2438--2446",
    ISBN = "979-8-89176-414-9",
    abstract = "This paper describes our participation in Task 11 of SemEval-2026, which evaluates the ability of models to determine logical validity of syllogisms independent of real-world content. We develop and compare three approaches for Subtask 1: (1) an encoder-based classification baseline using both classical ML methods and fine-tuned BERT with debiasing strategies; (2) an autoformalization pipeline combining DPO-aligned models with first order logic translation and formal inference via Prover9; and (3) a hybrid neuro-symbolic approach using GPT to generate OWL 2 ontologies evaluated with the HermiT reasoner. Our best result was achieved by the encoder-based classifier, obtaining a 72.25{\textbackslash}{\%} accuracy and a combined score of 20.37, placing 40th out of 45 participating teams. Analysis shows that classification methods exhibit lower content bias, autoformalization approaches suffer from translation inconsistencies and syntax incompatibilities, and ontology-based reasoning is hindered by prompt design limitations and verbose serialization formats. All our code can be found in the paper{'}s repository."
}