arXiv AI

Complexity of Grounded Semantics and Preferred Semantics in Finitary Argumentation Frameworks

The paper investigates the computational complexity of grounded and preferred semantics in computably finitary abstract argumentation frameworks (AFs). It maps key decision problems—credulous acceptance, skeptical acceptance, extension existence, uniqueness, and non‑empty existence—showing that for grounded semantics many are Σ₁⁰-complete or trivial, while for preferred semantics the problems fall into Σ₁⁰, Σ₂⁰, Σ₁ⁱ, and Σ₂ⁱ classes. The results delineate exactly where finitarity reduces complexity to the arithmetical hierarchy and where second‑order quantification pushes problems back into the analytical hierarchy.

arXiv Computation and Language
Sep 11

The Semantic Elevation Operator and the Closure of the Undecidable Class under Preservation

The paper introduces a semantic elevation operator that transforms static semantic questions about a program into dynamic questions about whether a property is preserved after the program rewrites itself. It proves that for intensional transformations the elevated property remains undecidable, showing that the class of non‑verifiable properties is closed under this operator and that repeated application climbs the arithmetical hierarchy to Υ02‑completeness. The work also demonstrates that no finite tower of verifiers can provide an unconditional certificate of preservation, and suggests a categorical perspective for future exploration.

By Jose Pascual Gumbau Mezquita
arXiv AI
Sep 24

A hierarchy of faithfulness criteria for knowledge base completion

The paper introduces a hierarchy of four increasingly strict faithfulness criteria—discrimination, logical admissibility, monotonic logical faithfulness, and probabilistic logical faithfulness—for evaluating knowledge base completion models, particularly when the target is a description logic knowledge base. It demonstrates that ranking accuracy alone does not guarantee logical faithfulness and shows that current embedding models fail to satisfy any of the criteria across the hierarchy. The authors provide a formal grounding for the strongest criterion using relative model counts and evaluate several models on εL ontologies, revealing gaps between performance metrics and logical correctness.

By Olga Mashkova, Robert Hoehndorf
Hugging Face Trending Papers
Jun 2

ZX-Calculus:Trace-Indexed Dependent Types and Epistemic Semantics

We propose ZX-Calculus (Knowledge Evolution Calculus), a conservative extension of Martin-Lof Dependent Type Theory (MLTT) integrating trace-indexed types, presheaf non-monotone semantics, and constructive AGM belief revision. A Coq mechanisation accompanies the paper (34 complete proofs; zero admits for the two central results).