A logic for default deontic reasoning

Fuente: arXiv
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Main Authors: Piazza, Mario, Sabatini, Andrea
Format: Preprint
Published: 2025
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author Piazza, Mario
Sabatini, Andrea
author_facet Piazza, Mario
Sabatini, Andrea
contents In many real-life settings, agents must navigate dynamic environments while reasoning under incomplete information and acting on a corpus of unstable, context-dependent, and often conflicting norms. We introduce a general, non-modal, proof-theoretic framework for deontic reasoning grounded in default logic. Its central feature is the notion of controlled sequent - a sequent annotated with sets of formulas (control sets) that prescribe what should or should not be entailed by the formulas in the antecedent. When combined with distinct extra-logical rules representing defaults and norms, these control sets record the conditions and constraints governing their applicability, thereby enabling local soundness checks for derived sequents. We prove that controlled sequent calculi satisfies admissibility of contraction and non-analytic cuts, and we establish their strong completeness with respect to credulous consequence in default theories and normative systems. Finally, we illustrate in depth how controlled sequent calculi provide a flexible and expressive basis for resolving deontic conflicts and capturing dynamic deontic notions via appropriate extra-logical rules.
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id arxiv_https___arxiv_org_abs_2512_18824
institution arXiv
publishDate 2025
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spellingShingle A logic for default deontic reasoning
Piazza, Mario
Sabatini, Andrea
Logic in Computer Science
Logic
In many real-life settings, agents must navigate dynamic environments while reasoning under incomplete information and acting on a corpus of unstable, context-dependent, and often conflicting norms. We introduce a general, non-modal, proof-theoretic framework for deontic reasoning grounded in default logic. Its central feature is the notion of controlled sequent - a sequent annotated with sets of formulas (control sets) that prescribe what should or should not be entailed by the formulas in the antecedent. When combined with distinct extra-logical rules representing defaults and norms, these control sets record the conditions and constraints governing their applicability, thereby enabling local soundness checks for derived sequents. We prove that controlled sequent calculi satisfies admissibility of contraction and non-analytic cuts, and we establish their strong completeness with respect to credulous consequence in default theories and normative systems. Finally, we illustrate in depth how controlled sequent calculi provide a flexible and expressive basis for resolving deontic conflicts and capturing dynamic deontic notions via appropriate extra-logical rules.
title A logic for default deontic reasoning
topic Logic in Computer Science
Logic
url https://arxiv.org/abs/2512.18824