Conway games, algebraically and coalgebraically

Using coalgebraic methods, we extend Conway's theory of games to possibly non-terminating, i.e. non-wellfounded games (hypergames). We take the view that a play which goes on forever is a draw, and hence rather than focussing on winning strategies, we focus on non-losing strategies. Hypergames...

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Main Authors: Furio Honsell, Marina Lenisa
Format: Article
Language:English
Published: Logical Methods in Computer Science e.V. 2011-09-01
Series:Logical Methods in Computer Science
Subjects:
Online Access:https://lmcs.episciences.org/703/pdf
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author Furio Honsell
Marina Lenisa
author_facet Furio Honsell
Marina Lenisa
author_sort Furio Honsell
collection DOAJ
description Using coalgebraic methods, we extend Conway's theory of games to possibly non-terminating, i.e. non-wellfounded games (hypergames). We take the view that a play which goes on forever is a draw, and hence rather than focussing on winning strategies, we focus on non-losing strategies. Hypergames are a fruitful metaphor for non-terminating processes, Conway's sum being similar to shuffling. We develop a theory of hypergames, which extends in a non-trivial way Conway's theory; in particular, we generalize Conway's results on game determinacy and characterization of strategies. Hypergames have a rather interesting theory, already in the case of impartial hypergames, for which we give a compositional semantics, in terms of a generalized Grundy-Sprague function and a system of generalized Nim games. Equivalences and congruences on games and hypergames are discussed. We indicate a number of intriguing directions for future work. We briefly compare hypergames with other notions of games used in computer science.
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spelling doaj.art-5e770556121642b58320d5d89b20ab462024-03-08T09:17:23ZengLogical Methods in Computer Science e.V.Logical Methods in Computer Science1860-59742011-09-01Volume 7, Issue 310.2168/LMCS-7(3:8)2011703Conway games, algebraically and coalgebraicallyFurio HonsellMarina LenisaUsing coalgebraic methods, we extend Conway's theory of games to possibly non-terminating, i.e. non-wellfounded games (hypergames). We take the view that a play which goes on forever is a draw, and hence rather than focussing on winning strategies, we focus on non-losing strategies. Hypergames are a fruitful metaphor for non-terminating processes, Conway's sum being similar to shuffling. We develop a theory of hypergames, which extends in a non-trivial way Conway's theory; in particular, we generalize Conway's results on game determinacy and characterization of strategies. Hypergames have a rather interesting theory, already in the case of impartial hypergames, for which we give a compositional semantics, in terms of a generalized Grundy-Sprague function and a system of generalized Nim games. Equivalences and congruences on games and hypergames are discussed. We indicate a number of intriguing directions for future work. We briefly compare hypergames with other notions of games used in computer science.https://lmcs.episciences.org/703/pdfcomputer science - logic in computer sciencef.3.2, f.4.1
spellingShingle Furio Honsell
Marina Lenisa
Conway games, algebraically and coalgebraically
Logical Methods in Computer Science
computer science - logic in computer science
f.3.2, f.4.1
title Conway games, algebraically and coalgebraically
title_full Conway games, algebraically and coalgebraically
title_fullStr Conway games, algebraically and coalgebraically
title_full_unstemmed Conway games, algebraically and coalgebraically
title_short Conway games, algebraically and coalgebraically
title_sort conway games algebraically and coalgebraically
topic computer science - logic in computer science
f.3.2, f.4.1
url https://lmcs.episciences.org/703/pdf
work_keys_str_mv AT furiohonsell conwaygamesalgebraicallyandcoalgebraically
AT marinalenisa conwaygamesalgebraicallyandcoalgebraically