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Rewriting on cyclic structures: Equivalence between the operational and the categorical description

Andrea Corradini, Fabio Gadducci (2010)

RAIRO - Theoretical Informatics and Applications

We present a categorical formulation of the rewriting of possibly cyclic term graphs, based on a variation of algebraic 2-theories. We show that this presentation is equivalent to the well-accepted operational definition proposed by Barendregt et al. – but for the case of circular redexes , for which we propose (and justify formally) a different treatment. The categorical framework allows us to model in a concise way also automatic garbage collection and rules for sharing/unsharing and...

Solving algebraic equations using coalgebra

Federico De Marchi, Neil Ghani, Christoph Lüth (2003)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Algebraic systems of equations define functions using recursion where parameter passing is permitted. This generalizes the notion of a rational system of equations where parameter passing is prohibited. It has been known for some time that algebraic systems in Greibach Normal Form have unique solutions. This paper presents a categorical approach to algebraic systems of equations which generalizes the traditional approach in two ways i) we define algebraic equations for locally finitely presentable...

Solving Algebraic Equations Using Coalgebra

Federico De Marchi, Neil Ghani, Christoph Lüth (2010)

RAIRO - Theoretical Informatics and Applications

Algebraic systems of equations define functions using recursion where parameter passing is permitted. This generalizes the notion of a rational system of equations where parameter passing is prohibited. It has been known for some time that algebraic systems in Greibach Normal Form have unique solutions. This paper presents a categorical approach to algebraic systems of equations which generalizes the traditional approach in two ways i) we define algebraic equations for locally finitely presentable ...

Strong functors and interleaving fixpoints in game semantics

Pierre Clairambault (2013)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

We describe a sequent calculus μLJ with primitives for inductive and coinductive datatypes and equip it with reduction rules allowing a sound translation of Gödel’s system T. We introduce the notion of a μ-closed category, relying on a uniform interpretation of open μLJ formulas as strong functors. We show that any μ-closed category is a sound model for μLJ. We then turn to the construction of a concrete μ-closed category based on Hyland-Ong game semantics. The model relies on three main ingredients:...

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