Abstract
The natural join and the inner union operations combine relations of a database. Tropashko and Spight realized that these two operations are the meet and join operations in a class of lattices, known by now as the relational lattices. They proposed then lattice theory as an algebraic approach to the theory of databases alternative to the relational algebra. Litak et al. proposed an axiomatization of relational lattices over the signature that extends the pure lattice signature with a constant and argued that the quasiequational theory of relational lattices over this extended signature is undecidable.
We prove in this paper that embeddability is undecidable for relational lattices. More precisely, it is undecidable whether a finite subdirectly-irreducible lattice can be embedded into a relational lattice. Our proof is a reduction from the coverability problem of a multimodal frame by a universal product frame and, indirectly, from the representability problem for relation algebras.
As corollaries we obtain the following results: the quasiequational theory of relational lattices over the pure lattice signature is undecidable and has no finite base; there is a quasiequation over the pure lattice signature which holds in all the finite relational lattices but fails in an infinite relational lattice.
Extended abstract, see [21] for a full version of this paper.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Notes
- 1.
In [13] such a lattice is called full relational lattice. The wording “class of relational lattices” is used there for the class of lattices that have an embedding into some lattice of the form \(\mathsf {R}(D,A)\).
- 2.
As P(A) is not totally ordered, we avoid calling a morphism “non expanding map” as it is often done in the literature.
References
Ackerman, N.: Completeness in generalized ultrametric spaces. P-Adic Numbers Ultrametric Anal. Appl. 5(2), 89–105 (2013)
Burris, S., Sankappanavar, H.: A Course in Universal Algebra. Dover Publications, Incorporated, Mineola (2012)
Codd, E.F.: A relational model of data for large shared data banks. Commun. ACM 13(6), 377–387 (1970)
Davey, B.A., Priestley, H.A.: Introduction to Lattices and Order. Cambridge University Press, New York (2002)
Evans, T.: Embeddability and the word problem. J. London Math. Soc. 28, 76–80 (1953)
Freese, R., Ježek, J., Nation, J.: Free lattices. American Mathematical Society, Providence (1995)
Grätzer, G.: General Lattice Theory. Birkhäuser Verlag, Basel (1998). New appendices by the author with Davey, B.A., Freese, R., Ganter, B., Greferath, M., Jipsen, P., Priestley, H.A., Rose, H., Schmidt, E.T., Schmidt, S.E., Wehrung, F., Wille, R
Hammack, R., Imrich, W., Klavzar, S.: Handbook of Product Graphs, 2nd edn. CRC Press Inc, Boca Raton (2011)
Hirsch, R., Hodkinson, I.: Representability is not decidable for finite relation algebras. Trans. Am. Math. Soc. 353, 1403–1425 (2001)
Hirsch, R., Hodkinson, I., Kurucz, A.: On modal logics between K \(\times \) K \(\times \) K and S5 \(\times \) S5 \(\times \) S5. J. Symb. Log. 67, 221–234 (2002)
Kurucz, A.: Combining modal logics. In: Patrick Blackburn, J.V.B., Wolter, F. (eds.) Handbook of Modal Logic Studies in Logic and Practical Reasoning, pp. 869–924. Elsevier, Amsterdam (2007)
Lawvere, F.W.: Metric spaces, generalized logic, closed categories. Rendiconti del Seminario Matematico e Fisico di Milano XLIII, 135–166 (1973)
Litak, T., Mikuls, S., Hidders, J.: Relational lattices: from databases to universal algebra. J. Logical Algebraic Methods Program. 85(4), 540–573 (2016)
Maddux, R.: The equational theory of \({C}{A}_{3}\) is undecidable. J. Symbolic Logic 45(2), 311–316 (1980)
Maddux, R.: Relation Algebras Studies in Logic and the Foundations of Mathematics. Elsevier, Amsterdam (2006)
Nation, J.B.: An approach to lattice varieties of finite height. Algebra Universalis 27(4), 521–543 (1990)
Priess-Crampe, S., Ribemboim, P.: Equivalence relations and spherically complete ultrametric spaces. C. R. Acad. Sci. Paris 320(1), 1187–1192 (1995)
Sambin, G.: Subdirectly irreducible modal algebras and initial frames. Studia Log. 62, 269–282 (1999)
Santocanale, L.: A duality for finite lattices. Preprint, September (2009). http://hal.archives-ouvertes.fr/hal-00432113
Santocanale, L.: Relational lattices via duality. In: Hasuo, I. (ed.) CMCS 2016. LNCS, vol. 9608, pp. 195–215. Springer, Cham (2016). doi:10.1007/978-3-319-40370-0_12
Santocanale, L.: The quasiequational theory of relational lattices, in the pure lattice signature. Preprint, July (2016). https://hal.archives-ouvertes.fr/hal-01344299
Spight, M., Tropashko, V.: Relational lattice axioms. Preprint (2008). http://arxiv.org/abs/0807.3795
Tropashko, V.: Relational algebra as non-distributive lattice. Preprint (2006). http://arxiv.org/abs/cs/0501053
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2017 Springer International Publishing AG
About this paper
Cite this paper
Santocanale, L. (2017). Embeddability into Relational Lattices Is Undecidable. In: Höfner, P., Pous, D., Struth, G. (eds) Relational and Algebraic Methods in Computer Science. RAMICS 2017. Lecture Notes in Computer Science(), vol 10226. Springer, Cham. https://doi.org/10.1007/978-3-319-57418-9_16
Download citation
DOI: https://doi.org/10.1007/978-3-319-57418-9_16
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-57417-2
Online ISBN: 978-3-319-57418-9
eBook Packages: Computer ScienceComputer Science (R0)