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Flexibly Graded Monads and Graded Algebras

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Mathematics of Program Construction (MPC 2022)

Abstract

When modelling side-effects using a monad, we need to equip the monad with effectful operations. This can be done by noting that each algebra of the monad carries interpretations of the desired operations. We consider the analogous situation for graded monads, which are a generalization of monads that enable us to track quantitative information about side-effects. Grading makes a significant difference: while many graded monads of interest can be equipped with similar operations, the algebras often cannot. We explain where these operations come from for graded monads. To do this, we introduce the notion of flexibly graded monad, for which the situation is similar to the situation for ordinary monads. We then show that each flexibly graded monad induces a canonical graded monad in such a way that operations for the flexibly graded monad carry over to the graded monad. In doing this, we reformulate grading in terms of locally graded categories, showing in particular that graded monads are a particular kind of relative monad. We propose that locally graded categories are a useful setting for work on grading in general.

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References

  1. Altenkirch, T., Chapman, J., Uustalu, T.: Monads need not be endofunctors. Log. Methods Comput. Sci 11(1), 3:1–3:40 (2015). https://doi.org/10.2168/lmcs-11(1:3)2015

  2. Dorsch, U., Milius, S., Schröder, L.: Graded monads and graded logics for the linear time - branching time spectrum. In: Fokkink, W., van Glabbeek, R. (eds.) Proc. of 30th Int. Conf. on Concurrency Theory, CONCUR 2019, Leibniz Int. Proc. in Informatics, vol. 140, pp. 36:1–36:16. Dagstuhl Publishing, SaarbrĂ¼cken/Wadern (2019). https://doi.org/10.4230/lipics.concur.2019.36

  3. Fritz, T., Perrone, P.: A probability monad as the colimit of spaces of finite samples. Theor. Appl. Categ. 34(7), 170–220 (2019). http://www.tac.mta.ca/tac/volumes/34/7/34-07abs.html

  4. Fujii, S., Katsumata, S., Melliès, P.-A.: Towards a formal theory of graded monads. In: Jacobs, B., Löding, C. (eds.) FoSSaCS 2016. LNCS, vol. 9634, pp. 513–530. Springer, Heidelberg (2016). https://doi.org/10.1007/978-3-662-49630-5_30

    Chapter  MATH  Google Scholar 

  5. Gaboardi, M., Katsumata, S., Orchard, D., Sato, T.: Graded hoare logic and its categorical semantics. In: ESOP 2021. LNCS, vol. 12648, pp. 234–263. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-72019-3_9

    Chapter  MATH  Google Scholar 

  6. Garner, R.: An embedding theorem for tangent categories. Adv. Math. 323, 668–687 (2018). https://doi.org/10.1016/j.aim.2017.10.039

    Article  MathSciNet  MATH  Google Scholar 

  7. Goncharov, S.: Trace semantics via generic observations. In: Heckel, R., Milius, S. (eds.) CALCO 2013. LNCS, vol. 8089, pp. 158–174. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-40206-7_13

    Chapter  Google Scholar 

  8. Gordon, R., Power, A.: Algebraic structure for bicategory enriched categories. J. Pure Appl. Algebra 130(2), 119–132 (1998). https://doi.org/10.1016/s0022-4049(97)00094-7

    Article  MathSciNet  MATH  Google Scholar 

  9. Katsumata, S.: Parametric effect monads and semantics of effect systems. In: Proceedings of 41st ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, POPL 2014, pp. 633–645. ACM Press, New York (2014). https://doi.org/10.1145/2535838.2535846

  10. Katsumata, S., McDermott, D., Uustalu, T., Wu, N.: Flexible presentations of graded monads. Proc. ACM Program. Lang. 6(ICFP), 123:1–123:29 (2022). https://doi.org/10.1145/3547654

  11. Kelly, G.M.: Basic Concepts of Enriched Category Theory, London Math. Soc. Lecture Note Series, vol. 64. Cambridge University Press, Cambridge (1982), reprinted as: Reprints Theor. Appl. Categ. 10 (2005). http://www.tac.mta.ca/tac/reprints/articles/10/tr10abs.html

  12. Kura, S.: Graded algebraic theories. In: FoSSaCS 2020. LNCS, vol. 12077, pp. 401–421. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-45231-5_21

    Chapter  Google Scholar 

  13. Levy, P.B.: Locally graded categories. Slides (2019). https://www.cs.bham.ac.uk/~pbl/papers/locgrade.pdf

  14. Lobbia, G.: Distributive laws for relative monads. arXiv preprint arXiv:2007.12982 [math.CT] (2020). https://arxiv.org/abs/2007.12982

  15. Marmolejo, F., Wood, R.J.: Monads as extension systems: No iteration is necessary. Theor. Appl. Categ. 24(4), 84–113 (2010). http://www.tac.mta.ca/tac/volumes/24/4/24-04abs.html

  16. Melliès, P.A.: Parametric monads and enriched adjunctions. Manuscript (2012). https://www.irif.fr/~mellies/tensorial-logic/8-parametric-monads-and-enriched-adjunctions.pdf

  17. Milius, S., Pattinson, D., Schröder, L.: Generic trace semantics and graded monads. In: Moss, L.S., SobociÅ„ski, P. (eds.) Proceedings of 6th Conference on Algebra and Coalgebra in Computer Science, CALCO 2015, Leibniz Int. Proceedings in Informatics, vol. 35, pp. 253–269. Dagstuhl Publishing, SaarbrĂ¼cken/Wadern (2015). https://doi.org/10.4230/lipics.calco.2015.253

  18. Moggi, E.: Computational lambda-calculus and monads. In: Proceedings of 4th Annual Symposium on Logic in Computer Science, LICS 1989, pp. 14–23. IEEE Press, Los Alamitos, CA (1989). https://doi.org/10.1109/lics.1989.39155

  19. Moggi, E.: Notions of computation and monads. Inf. Comput. 93(1), 55–92 (1991). https://doi.org/10.1016/0890-5401(91)90052-4

    Article  MathSciNet  MATH  Google Scholar 

  20. Mycroft, A., Orchard, D., Petricek, T.: Effect systems revisited—control-flow algebra and semantics. In: Probst, C.W., Hankin, C., Hansen, R.R. (eds.) Semantics, Logics, and Calculi. LNCS, vol. 9560, pp. 1–32. Springer, Cham (2016). https://doi.org/10.1007/978-3-319-27810-0_1

    Chapter  MATH  Google Scholar 

  21. Plotkin, G., Power, J.: Algebraic operations and generic effects. Appl. Categ. Struct. 11, 69–94 (2003). https://doi.org/10.1023/a:1023064908962

    Article  MathSciNet  MATH  Google Scholar 

  22. Smirnov, A.: Graded monads and rings of polynomials. J. Math. Sci. 151(3), 3032–3051 (2008). https://doi.org/10.1007/s10958-008-9013-7

    Article  MathSciNet  MATH  Google Scholar 

  23. Staton, S.: An algebraic presentation of predicate logic. In: Pfenning, F. (ed.) FoSSaCS 2013. LNCS, vol. 7794, pp. 401–417. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-37075-5_26

    Chapter  MATH  Google Scholar 

  24. Street, R.: Two constructions on lax functors. Cah. Topol. Géom. Diff. Catég. 13(3), 217–264 (1972). http://www.numdam.org/item/CTGDC_1972__13_3_217_0

  25. Ulmer, F.: Properties of dense and relative adjoint functors. J. Algebra 8(1), 77–95 (1968). https://doi.org/10.1016/0021-8693(68)90036-7

    Article  MathSciNet  MATH  Google Scholar 

  26. Wood, R.J.: Indicial Methods for Relative Categories. Ph.D. thesis, Dalhousie University (1976). http://hdl.handle.net/10222/55465

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Acknowledgements

We thank Nathanael Arkor, Shin-ya Katsumata and Nicolas Wu for helpful discussions. Both authors were supported by the Icelandic Research Fund grants no. 196323-053 and 228684-051.

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Correspondence to Dylan McDermott .

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McDermott, D., Uustalu, T. (2022). Flexibly Graded Monads and Graded Algebras. In: Komendantskaya, E. (eds) Mathematics of Program Construction. MPC 2022. Lecture Notes in Computer Science, vol 13544. Springer, Cham. https://doi.org/10.1007/978-3-031-16912-0_4

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  • DOI: https://doi.org/10.1007/978-3-031-16912-0_4

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