Hostname: page-component-8448b6f56d-c4f8m Total loading time: 0 Render date: 2024-04-24T15:22:25.276Z Has data issue: false hasContentIssue false

Coproducts of Ideal Monads

Published online by Cambridge University Press:  15 October 2004

Neil Ghani
Affiliation:
Department of Mathematics and Computer Science, University of Leicester, University Road, Leicester LE1 7RH, UK; ng13@mcs.le.ac.uk.
Tarmo Uustalu
Affiliation:
Institute of Cybernetics, Tallinn Technical University, Akadeemia tee 21, EE-12618 Tallinn, Estonia; tarmo@cs.ioc.ee.
Get access

Abstract

The question of how to combine monads arises naturally in many areas with much recent interest focusing on the coproduct of two monads. In general, the coproduct of arbitrary monads does not always exist. Although a rather general construction was given by Kelly  [Bull.  Austral. Math. Soc.22 (1980) 1–83], its generality is reflected in its complexity which limits the applicability of this construction. Following our own research [C. Lüth and N. Ghani, Lect. Notes Artif. Intell.2309 (2002) 18–32], and that of Hyland, Plotkin and Power [IFIP Conf. Proc.223 (2002) 474–484], we are looking for specific situations when simpler constructions are available. This paper uses fixed points to give a simple construction of the coproduct of two ideal monads.

Keywords

Type
Research Article
Copyright
© EDP Sciences, 2004

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Aczel, P., Adámek, J., Milius, S. and Velebil, J., Infinite trees and completely iterative theories: a coalgebraic view. Theor. Comput. Sci. 300 (2003) 145. CrossRef
Adámek, J., Milius, S. and Velebil, J., Free iterative theories: a coalgebraic view. Math. Struct. Comput. Sci. 13 (2003) 259320. CrossRef
J. Adámek and J. Rosický, Locally Presentable and Accessible Categories. London Math. Soc. Lect. Note Ser. 189 (1994).
Barr, M., Coequalizers and free triples. Math. Z. 116 (1970) 307322. CrossRef
M. Barr and C. Wells, Toposes, Triples and Theories. Grundlehren der mathematischen Wissenschaften 275 (1985).
Beck, J., Distributive laws, in Seminar on Triples and Categorical Homology Theory (ETH, 1966/67), edited by B. Eckmann, Springer-Verlag, Berlin. Lect. Notes Math. 80 (1969) 119140. CrossRef
M. Fiore, G. Plotkin and D. Turi, Abstract syntax and variable binding, in Proc. of 14th Ann. IEEE Symp. on Logic in Computer Science, LICS'99, Trento, July 1999, IEEE CS Press, Los Alamitos, CA (1999) 193–202.
Ghani, N., Lüth, C., de Marchi, F. and Power, J., Dualising initial algebras. Math. Struct. Comput. Sci. 13 (2003) 349370. CrossRef
N. Ghani, C. Lüth and F. De Marchi, Coalgebraic monads, in Proc. of 5th Wksh. on Coalgebraic Methods in Computer Science, CMCS'02, Grenoble, Apr. 2002, edited by L.S. Moss, Elsevier, Amsterdam. Electr. Notes in Theor. Comput. Sci. 65 (2002).
N. Ghani and T. Uustalu, Explicit substitutions and higher-order syntax, in Proc. of 2nd ACM SIGPLAN Wksh. on Mechanized Reasoning about Languages with Variable Binding, MERLIN'03, Uppsala, Aug. 2003, edited by F. Honsell, M. Miculan, A. Momigliano, ACM Press, New York (2003).
Goguen, J.A., A categorical manifesto. Math. Struct. Comput. Sci. 1 (1991) 4967. CrossRef
Hyland, M., Plotkin, G. and Power, J., Combining computational effects: commutativity and sum, in Proc. of IFIP 17th World Computer Congress, TC1 Stream / 2nd IFIP Int. Conf. on Theoretical Computer Science, TCS 2002 , Montreal, Aug. 2002, edited by A. Baeza-Yates, U. Montanari, and N. Santoro, Kluwer Academic Publishers, Dordrecht. IFIP Conf. Proc. 223 (2002) 474484.
C. Jones and G.D. Plotkin, A probabilistic powerdomain of evaluations, in Proc. of 4th Ann. IEEE Symp. Logic in Computer Science, LICS'89, Pacific Grove, CA, June 1989, IEEE CS Press, Washington, DC (1989) 186–195.
M. Jones and L. Duponcheel, Composing monads, Techn. report RR-1004. Dept. of Comp. Sci. Yale Univ. (1993).
Kelly, G.M., A unified treatment of transfinite constructions for free algebras, free monoids, colimits, associated sheaves and so on. Bull. Austral. Math. Soc. 22 (1980) 183. CrossRef
Kelly, G.M. and Power, J., Adjunctions whose counits are equalizers, and presentations of finitary monads. J. Pure Appl. Algebra 89 (1993) 163179. CrossRef
F.E.J. Linton, Some aspects of equational categories, in Proc. of Conf. on Categorical Algebra, La Jolla, CA, June 1965, edited by S. Eilenberg, D. K. Harrison, S. Mac Lane, H. Röhrl, Springer-Verlag, Berlin (1966) 84–94.
C. Lüth, Categorical Term Rewriting: Monads and Modularity. Ph.D. Thesis, Lab. for Foundations of Comp. Sci., Univ. of Edinburgh (1998).
Lüth, C. and Ghani, N., Monads and modularity, in Proc. of 4th Int. Wksh. on Frontiers of Combining Systems, FroCoS 2002 , Santa Margherita Ligure, Apr. 2002, edited by A. Armando, Springer-Verlag, Berlin. Lect. Notes Artif. Intell. 2309 (2002) 1832.
Lüth, C. and Ghani, N., Monads and modular term rewriting, in Proc. of 7th Int. Conf. on Category Theory in Computer Science, CTCS'97, Santa Margherita Ligure, Sept. 2002, edited by E. Moggi and G. Rosolini, Springer-Verlag, Berlin. Lect. Notes Comput. Sci. 1290 (1997) 6986. CrossRef
E.G. Manes, Algebraic Theories. Springer-Verlag, Berlin, Grad. Texts in Math. 26 (1976).
R. Matthes and T. Uustalu, Substitution in non-wellfounded syntax with variable binding, in Proc. of 6th Wksh. on Coalgebraic Methods in Computer Science, CMCS'03, Warsaw, Apr. 2003, edited by H. P. Gumm, Elsevier, Amsterdam. Electr. Notes Theor. Comput. Sci. 82 (2003).
Mislove, M., Nondeterminism and probabilistic choice: obeying the laws, in Proc. 11 Int. Conf. on Concurrency Theory, CONCUR 2000 , University Park, PA, Aug. 2000, edited by C. Palamidessi, Springer-Verlag, Berlin. Lect. Notes comput. Sci. 1877 (2000) 350364. CrossRef
E. Moggi, Computational lambda-calculus and monads, in Proc. of 4th Ann. IEEE Symp. on Logic in Computer Science, LICS'89, Pacific Grove, CA, June 1989, IEEE CS Press, Washington, DC (1989) 14–23.
E. Moggi, An abstract view of programming languages. Techn. report ECS-LFCS-90-113, Lab. for Foundations of Comp. Sci., Univ. of Edinburgh (1990).
Moss, L., Parametric corecursion. Theor. Comput. Sci. 260 (2001) 139163. CrossRef
R. Tix, Continuous D-cones: convexity and powerdomain constructions. Ph.D. Thesis, Techn. Univ. Darmstadt (1999).
D. Varacca, The powerdomain of indexed valuations, in Proc. of 17th Ann. IEEE Symp. on Logic in Computer Science, LICS'02, Copenhagen, July 2002, IEEE CS Press, Los Alamitos, CA (2002) 299–308.