Structured Abductive-Deductive-Inductive Reasoning for LLMs via Algebraic Invariants
Abstract
Large language models exhibit systematic limitations in structured logical reasoning: they conflate hypothesis generation with verification, cannot distinguish conjecture from validated knowledge, and allow weak reasoning steps to propagate unchecked through inference chains. We present a symbolic reasoning scaffold that operationalizes Peirce's tripartite inference -- abduction, deduction, and induction -- as an explicit protocol for LLM-assisted reasoning. The framework enforces logical consistency through five algebraic invariants (the Gamma Quintet), the strongest of which -- the Weakest Link bound -- ensures that no conclusion in a reasoning chain can exceed the reliability of its least-supported premise. This principle, independently grounded as weakest link resolution in possibilistic logic and empirically validated for chain-of-thought reasoning, prevents logical inconsistencies from accumulating across multi-step inference. We verify all invariants through a property-based testing suite of 100 properties and 16 fuzz tests over 10^5+ generated cases, providing a verified reference implementation of the invariants suitable as a foundation for future reasoning benchmarks.
Keywords
Cite
@article{arxiv.2604.15727,
title = {Structured Abductive-Deductive-Inductive Reasoning for LLMs via Algebraic Invariants},
author = {Sankalp Gilda and Shlok Gilda},
journal= {arXiv preprint arXiv:2604.15727},
year = {2026}
}
Comments
10 pages + 3 pages references. Accepted as a poster at the ICLR 2026 Workshop for LLM Reasoning