eprintid: 10160498 rev_number: 8 eprint_status: archive userid: 699 dir: disk0/10/16/04/98 datestamp: 2023-05-19 12:46:22 lastmod: 2023-05-19 12:46:22 status_changed: 2023-05-19 12:46:22 type: article metadata_visibility: show sword_depositor: 699 creators_name: Carreiro, Facundo creators_name: Facchini, Alessandro creators_name: Venema, Yde creators_name: Zanasi, Fabio title: Model theory of monadic predicate logic with the infinity quantifier ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F48 keywords: Monadic first-order logic, Generalised quantifier, Infinity quantifier, Characterisation theorem, Preservation theorem, Continuity note: © The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. abstract: This paper establishes model-theoretic properties of ME∞, a variation of monadic first-order logic that features the generalised quantifier ∃ ∞ (‘there are infinitely many’). We will also prove analogous versions of these results in the simpler setting of monadic first-order logic with and without equality (ME and M, respectively). For each logic L∈ { M, ME, ME∞} we will show the following. We provide syntactically defined fragments of L characterising four different semantic properties of L-sentences: (1) being monotone and (2) (Scott) continuous in a given set of monadic predicates; (3) having truth preserved under taking submodels or (4) being truth invariant under taking quotients. In each case, we produce an effectively defined map that translates an arbitrary sentence φ to a sentence φp belonging to the corresponding syntactic fragment, with the property that φ is equivalent to φp precisely when it has the associated semantic property. As a corollary of our developments, we obtain that the four semantic properties above are decidable for L-sentences. date: 2021-10-27 date_type: published publisher: SPRINGER HEIDELBERG official_url: http://doi.org/10.1007/s00153-021-00797-0 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1593662 doi: 10.1007/s00153-021-00797-0 lyricists_name: Zanasi, Fabio lyricists_id: FZANA74 actors_name: Zanasi, Fabio actors_id: FZANA74 actors_role: owner full_text_status: public publication: Archive for Mathematical Logic volume: 61 pagerange: 465-502 pages: 38 issn: 0933-5846 citation: Carreiro, Facundo; Facchini, Alessandro; Venema, Yde; Zanasi, Fabio; (2021) Model theory of monadic predicate logic with the infinity quantifier. Archive for Mathematical Logic , 61 pp. 465-502. 10.1007/s00153-021-00797-0 <https://doi.org/10.1007/s00153-021-00797-0>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10160498/1/s00153-021-00797-0.pdf