Model completions for universal classes of algebras: necessary and sufficient conditions

Metcalfe, George; Reggio, Luca (2023). Model completions for universal classes of algebras: necessary and sufficient conditions. The journal of symbolic logic, 88(1), pp. 381-417. Cambridge University Press 10.1017/jsl.2022.1

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Necessary and sufficient conditions are presented for the (first-order) theory of a universal class of algebraic structures (algebras) to admit a model completion, extending a characterization provided by Wheeler. For varieties of algebras that have equationally definable principal congruences and the compact intersection property, these conditions yield a more elegant characterization obtained (in a slightly more restricted setting) by Ghilardi and Zawadowski. Moreover, it is shown that under certain further assumptions on congruence lattices, the existence of a model completion implies that the variety has equationally definable principal congruences. This result is then used to provide necessary and sufficient conditions for the existence of a model completion for theories of Hamiltonian varieties of pointed residuated lattices, a broad family of varieties that includes lattice-ordered abelian groups and MV-algebras. Notably, if the theory of a Hamiltonian variety of pointed residuated lattices admits a model completion, it must have equationally definable principal congruences. In particular, the theories of lattice-ordered abelian groups and MV-algebras do not have a model completion, as first proved by Glass and Pierce, and Lacava, respectively. Finally, it is shown that certain varieties of pointed residuated lattices generated by their linearly ordered members, including lattice-ordered abelian groups and MV-algebras, can be extended with a binary operation in order to obtain theories that do have a model completion.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Mathematics and Statistics > Institute of Mathematics

UniBE Contributor:

Metcalfe, George, Reggio, Luca

Subjects:

500 Science > 510 Mathematics

ISSN:

0022-4812

Publisher:

Cambridge University Press

Language:

English

Submitter:

George Metcalfe

Date Deposited:

27 Feb 2023 08:09

Last Modified:

27 Feb 2023 23:27

Publisher DOI:

10.1017/jsl.2022.1

ArXiv ID:

2102.01426v2

BORIS DOI:

10.48350/179278

URI:

https://boris.unibe.ch/id/eprint/179278

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