Abstract
In this paper, we study projective algebras in varieties of (bounded) commutative integral residuated lattices. We make use of a well-established construction in residuated lattices, the ordinal sum, and the order property of divisibility. Via the connection between projective and splitting algebras, we show that the only finite projective algebra in \(\mathsf {{FL}_{ew}}\) is the two-element Boolean algebra. Moreover, we show that several interesting varieties have the property that every finitely presented algebra is projective, such as locally finite varieties of hoops. Furthermore, we show characterization results for finite projective Heyting algebras, and finitely generated projective algebras in locally finite varieties of bounded hoops and BL-algebras. Finally, we connect our results with the algebraic theory of unification.
Similar content being viewed by others
Data availability
Data sharing not applicable to this article as no datasets were generated or analysed during the current study.
References
Aglianò, P.: Splittings in GBL-algebras I: the general case. Fuzzy Sets Syst. 373, 1–18 (2019)
Aglianò, P.: Splittings in GBL-algebras II: the representable case. Fuzzy Sets Syst. 373, 19–36 (2019)
Aglianò, P.: Varieties of BL-algebras III: splitting algebras. Stud. Log. 107, 1235–1259 (2019)
Aglianò, P.: A short note on divisible residuated semilattices. Soft Comput. 24, 259–266 (2020)
Aglianò, P., Ferreirim, I., Montagna, F.: Basic hoops: an algebraic study of continuous \(t\)-norms. Stud. Log. 87(1), 73–98 (2007)
Aglianò, P., Montagna, F.: Varieties of BL-algebras I: general properties. J. Pure Appl. Algebra 181, 105–129 (2003)
Aglianò, P., Ugolini, S.: MTL-algebras as rotations of basic hoops. J. Logic Comput. 20, 763–784 (2021)
Aglianò, P., Ugolini, S.: Projectivity and unification in substructural logics of generalized rotations (2022). Submitted
Aglianò, P., Ursini, A.: On subtractive varieties II: general properties. Algebra Univ. 36, 222–259 (1996)
Bahls, P., Cole, J., Galatos, N., Jipsen, P., Tsinakis, C.: Cancellative residuated lattices. Algebra Univers. 50, 83–106 (2003)
Balbes, R.: Projective and injective distributive lattices. Pacific. J. Math. 21, 405–420 (1967)
Balbes, R., Horn, A.: Injective and projective Heyting algebras. Trans. Amer. Math. Soc. 148, 549–559 (1970)
Beynon, W.: Applications of duality in the theory of finitely generated lattice-ordered abelian groups. Can. J. Math. 29, 243–254 (1977)
Blok, W., Ferreirim, I.: Hoops and their implicational reducts (abstract). Algebr. Methods Logic Comput. Sci. Banach Center Publ. 28, 219–230 (1993)
Blok, W., Ferreirim, I.: On the structure of hoops. Algebra Univers. 43, 233–257 (2000)
Blok, W., Pigozzi, D.: Algebraizable Logics. No. 396 in Mem. of the Amer. Math. Soc. American Mathematical Society, Providence, Rhode Island (1989)
Blok, W., Pigozzi, D.: On the structure of varieties with equationally definable principal congruences III. Algebra Univers. 32, 545–608 (1994)
Blok, W., Raftery, J.: Varieties of commutative residuated integral pomonoids and their residuation subreducts. J. Algebra 190, 280–328 (1997)
Blount, K., Tsinakis, C.: The structure of residuated lattices. Internat. J. Algebra Comput. 13(4), 437–461 (2003)
Burris, S., Sankappanavar, H.: A Course in Universal Algebra. Graduate Texts in Mathematics. Springer, Berlin (1981)
Cabrer, L., Mundici, D.: Projective MV-algebras and rational polyhedra. Algebra Univers. 62, 63–74 (2009)
Castaño, D., Varela, J.D., Torrens, A.: Free-decomposability in varieties of pseudocomplemented residuated lattices. Stud. Log. 98, 223–235 (2011)
Cignoli, R., Torrens, A.: Glivenko like theorems in natural expansions of BCK-logic. Math. Log. Q. 50, 111–125 (2004)
Cignoli, R., Torrens, A.: Varieties of commutative integral bounded residuated lattices admitting a Boolean retraction term. Stud. Log. 100, 1107–1136 (2012)
D’Antona, O., Marra, V.: Computing coproducts of finitely presented Gödel algebras. Ann. Pure Appl. Logic 142, 202–211 (2006)
Di Nola, A., Grigolia, R., Lettieri, A.: Projective MV-algebras. Int. J. Approx. Reason. 47, 323–332 (2008)
Di Nola, A., Lettieri, A.: Perfect MV-algebras are categorically equivalent to abelian \(\ell \)-groups. Stud. Log. 53, 417–432 (1994)
Dzik, W.: Unification in some substructural logics of BL-algebras and hoops. Rep. Math. Log. 43, 73–83 (2008)
Esteva, F., Godo, L.: Monoidal t-norm based logic: towards a logic for left-continuous t-norms. Fuzzy Sets Syst. 124, 271–288 (2001)
Ferreirim, I.: On a conjecture by Andrzej Wroński for BCK-algebras and subreducts of hoops. Scient. Math. Japonica. 53, 119–132 (2001)
Gabriel, P., Ullmer, F.: Lokar Präsentiertbare Kategorien. No. 221 in Lecture Notes in Mathematics. Springer, Berlin (1971)
Galatos, N.: Minimal varieties of residuated lattices. Algebra Univers. 52(2), 215–239 (2005)
Galatos, N., Jipsen, P., Kowalski, T., Ono, H.: Residuated Lattices: An Algebraic Glimpse at Substructural Logics, Studies in Logics and the Foundations of Mathematics, vol. 151. Elsevier, Amsterdam (2007)
Ghilardi, S.: Unification through projectivity. J. Logic Comput. 7, 733–752 (1997)
Ghilardi, S.: Unification in intuitionistic logic. J. Symb. Log. 64, 859–890 (1999)
Gumm, H., Ursini, A.: Ideals in universal algebra. Algebra Univers. 19, 45–54 (1984)
Hájek, P.: Metamathematics of Fuzzy Logic. No. 4 in Trends in Logic—Studia Logica Library. Kluwer Academic Publications, Dordrecht (1998)
Iséki, K.: An algebra related with a propositional calculus. Proc. Japan. Acad. 41, 26–29 (1962)
Jipsen, P., Tsinakis, C.: A survey of residuated lattices. In: Martinez, J. (ed.) Ordered Algebraic Structures, pp. 19–56. Kluwer Academic Publisher, Dordrecht (1982)
Olson, J.S., Alten, C.V.: Structural completeness in substructural logics. Logic J. IGPL 16(5), 453–495 (2008)
Köhler, P.: Brouwerian semilattices. Trans. Amer. Math. Soc. 20, 103–126 (1981)
Kowalski, T., Ono, H.: Splitting in the variety of residuated lattices. Algebra Univers. 44, 283–298 (2000)
Marra, V., Spada, L.: Duality, projectivity, and unification in łukasiewicz logic and MV-algebras. Ann. Pure Appl. Logic 164, 192–210 (2013)
McKenzie, R.: Equational bases and nonmodular lattice varieties. Trans. Amer. Math. Soc. 174, 1–43 (1972)
Nation, J.: Finite sublattices of a free lattice. Trans. Amer. Math. Soc. 269, 311–337 (1982)
Nishimura, I.: On formulas of one variable in intuitionistic propositional calculus. J. Symb. Log. 25, 327–331 (1960)
Ono, H., Komori, Y.: Logics without the contraction rule. J. Symb. Log. 50, 169–201 (1985)
Quackenbush, R.: Demi-semi-primal algebras and Mal’cev type conditions. Math. Z. 122, 166–176 (1971)
Quillen, D.: Projective modules over polynomial rings. Invent. Math. 36, 167–171 (1976)
Robinson, J.: A machine-oriented logic based on the resolution principle. J. ACM 12, 23–41 (1965)
Spinks, M., Veroff, R.: On a homomorphism property of hoops. Bull. Sect. Logic 33, 135–142 (2004)
Ugolini, S.: The polyhedral geometry of Wajsberg hoops (2022). arXiv:2201.07009 (Submitted)
Ward, L., Dilworth, R.: Residuated lattices. Trans. Amer. Math. Soc. 45, 335–354 (1939)
Whitman, P.: Free lattices. Ann. Math. 42, 325–330 (1941)
Acknowledgements
The authors wish to thank the anonymous referee who suggested an improvement of Lemma 3.1. The authors declare that this work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant agreement No 890616 awarded to Ugolini.
Author information
Authors and Affiliations
Corresponding author
Additional information
Presented by N. Galatos.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Aglianò, P., Ugolini, S. Projectivity in (bounded) commutative integral residuated lattices. Algebra Univers. 84, 2 (2023). https://doi.org/10.1007/s00012-022-00798-x
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s00012-022-00798-x