Tag
decidability
- Jun 14, 2026 Context-Sensitive Rules and Why Non-Contracting Rewriting Is Decidable A rule may rewrite a symbol in the context of its neighbours as long as it never shortens the string, and that single restriction turns an unbounded search into a finite one. computation theory
- Feb 27, 2026 Inclusion Dependencies and the Undecidability That Follows Them How inclusion dependencies generalize foreign keys across arbitrary attribute sets, why their implication problem needs infinite chase sequences, and what breaks when they are combined with functional dependencies. databases
- Apr 13, 2023 Presburger Arithmetic and the Decidable Side of Number Theory Why the first-order theory of addition alone admits quantifier elimination and always terminates, and how the single operation of multiplication moves the same language across the undecidability line. computation theory