{"slug": "which-models-perform-better-in-inheritance-reasoning", "title": "Which Models Perform Better in Inheritance Reasoning?", "summary": "Researchers from PSL compared commercial and open-source large language models on Arabic Islamic inheritance reasoning, finding commercial models significantly more reliable. Gemini 2.5 Flash achieved the best performance with a mean relative error of 0.989, while open-source models showed instability in multi-step legal reasoning.", "body_md": "arXiv:2606.13751v1 Announce Type: new\nAbstract: This paper presents the participation of team PSL in the QIAS 2026 Shared Task on Arabic Islamic inheritance reasoning. The task evaluates the ability of large language models to solve inheritance cases that require legal interpretation, multi-step reasoning, and precise numerical computation. We compare \\textit{commercial} and \\textit{open-source} models under a unified prompting strategy to assess their effectiveness in structured legal reasoning with minimal task-specific adaptation. \\\\ Our results show a clear gap in reliability between the two model families. Commercial models demonstrate stronger performance in identifying eligible heirs, applying exclusion rules, and maintaining consistency across reasoning steps. In contrast, open-source models exhibit greater instability, particularly in cases involving dependent legal decisions and fractional share adjustments. The best performance is achieved by \\textit{Gemini 2.5 Flash}, with an MRE of $0.989$.", "url": "https://wpnews.pro/news/which-models-perform-better-in-inheritance-reasoning", "canonical_source": "https://arxiv.org/abs/2606.13751", "published_at": "2026-06-15 04:00:00+00:00", "updated_at": "2026-06-15 04:16:15.467336+00:00", "lang": "en", "topics": ["large-language-models", "ai-research"], "entities": ["PSL", "Gemini 2.5 Flash", "QIAS 2026"], "alternates": {"html": "https://wpnews.pro/news/which-models-perform-better-in-inheritance-reasoning", "markdown": "https://wpnews.pro/news/which-models-perform-better-in-inheritance-reasoning.md", "text": "https://wpnews.pro/news/which-models-perform-better-in-inheritance-reasoning.txt", "jsonld": "https://wpnews.pro/news/which-models-perform-better-in-inheritance-reasoning.jsonld"}}