FLAP Journal 2025 Journal Article
Some Polyadic Modal Boolean Algebras are Gaggles
- Nicholas Ferenz
- Andrew Tedder
J. Michael Dunn [4] introduced gaggle theory, which develops a close cor- respondence between certain kinds of algebras (called gaggles) and relational semantics. The gaggle framework has been applied to many propositional log- ics with much success. This paper is a foray into first-order logic via gaggle- theory. We show that monadic and polyadic Boolean algebras, introduced by Halmos [10] as algebraic structures to study first-order logic, are Boolean gaggles (in the sense of [3]), and that their extensions with certain kinds of operations are multi-gaggles. We show these algebraic structures to have representations in terms of, and embeddings in, relational semantics, using the gaggle-theoretic framework. That is, we employ relations to model all the operations, includ- ing those representing the quantifiers and variable substitutions. This project provides a foundation to explore first-order extensions of a wide range of logics. 2020 Mathematics Subject Classification. Primary: 03B45, Secondary: 03G15. ∗ NF acknowledges funding from by RVO 67985807 and that this work is also financed by national funds through FCT — Fundação para a Ciência e a Tecnologia, I. P. , under the scope of UIDB/00310/2020 project, identified as DOI 10. 54499/UIDB/00310/2020. † AT was funded by the DFG project TE 1611/1-1.