Zobrazeno 1 - 10
of 63
pro vyhledávání: '"Michael C. Laskowski"'
Autor:
SAMUEL BRAUNFELD, MICHAEL C. LASKOWSKI
Publikováno v:
The Journal of Symbolic Logic. 87:1130-1155
We show that if a countable structure $M$ in a finite relational language is not cellular, then there is an age-preserving $N \supseteq M$ such that $2^{\aleph_0}$ many structures are bi-embeddable with $N$. The proof proceeds by a case division base
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::47e67ee51dc45f9b36f8eb908f46f8cb
https://doi.org/10.1017/jsl.2022.3
https://doi.org/10.1017/jsl.2022.3
Autor:
Michael C. Laskowski, Douglas Ulrich
Publikováno v:
The Journal of Symbolic Logic. 88:418-426
We prove that many seemingly simple theories have Borel complete reducts. Specifically, if a countable theory has uncountably many complete one-types, then it has a Borel complete reduct. Similarly, if $Th(M)$ is not small, then $M^{eq}$ has a Borel
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::441760eb959926d75e62866ee3dbf666
https://doi.org/10.1017/jsl.2021.78
https://doi.org/10.1017/jsl.2021.78
Autor:
Michael C. Laskowski, Samuel Braunfeld
We give several characterizations of when a complete first-order theory $T$ is monadically NIP, i.e. when expansions of $T$ by arbitrary unary predicates do not have the independence property. The central characterization is a condition on finite sat
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e2c4afa154d0464f045f258a69e13562
Autor:
Samuel Braunfeld, Michael C. Laskowski
Given a complete theory $T$ and a subset $Y \subseteq X^k$, we precisely determine the {\em worst case complexity}, with respect to further monadic expansions, of an expansion $(M,Y)$ by $Y$ of a model $M$ of $T$ with universe $X$. In particular, alt
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8633ed24ed186e7ac3ec119b36d0f1b3
Publikováno v:
The Journal of Symbolic Logic. 82:98-119
We introduce the concept of a locally finite abstract elementary class and develop the theory of disjoint$\left( { \le \lambda ,k} \right)$-amalgamation) for such classes. From this we find a family of complete ${L_{{\omega _1},\omega }}$ sentences $
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::a43f4c06a4e5f5a9b1f83d31ffd11722
https://doi.org/10.1017/jsl.2016.25
https://doi.org/10.1017/jsl.2016.25
Autor:
Samuel Braunfeld, Michael C. Laskowski
We prove two results intended to streamline proofs about cellularity that pass through mutual algebraicity. First, we show that a countable structure $M$ is cellular if and only if $M$ is $\omega$-categorical and mutually algebraic. Second, if a coun
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7ecb275088fc3891b9cd8bccda9fe699
http://arxiv.org/abs/1911.06303
http://arxiv.org/abs/1911.06303
Publikováno v:
The Journal of Symbolic Logic. 81:1142-1162
We introduce the notion of pseudoalgebraicity to study atomic models of first order theories (equivalently models of a complete sentence of ${L_{{\omega _1},\omega }}$). Theorem: Let T be any complete first-order theory in a countable language with a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::c85683ec46eaa38d94ec87b4c45db17d
https://doi.org/10.1017/jsl.2015.81
https://doi.org/10.1017/jsl.2015.81
Autor:
Gabriel Conant, Michael C. Laskowski
Fix a weakly minimal (i.e., superstable $U$-rank $1$) structure $\mathcal{M}$. Let $\mathcal{M}^*$ be an expansion by constants for an elementary substructure, and let $A$ be an arbitrary subset of the universe $M$. We show that all formulas in the e
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e7df56a31ac5778982a79a5a101267af
http://arxiv.org/abs/1809.04940
http://arxiv.org/abs/1809.04940
Autor:
Michael C. Laskowski, Caroline Terry
Publikováno v:
Notre Dame J. Formal Logic 61, no. 2 (2020), 265-282
We define an easily verifiable notion of an atomic formula having uniformly bounded arrays in a structure $M$. We prove that if $T$ is a complete $L$-theory, then $T$ is mutually algebraic if and only if there is some model $M$ of $T$ for which every
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3e40bcb0a59395d2728325cef8ba0c84
http://arxiv.org/abs/1803.10054
http://arxiv.org/abs/1803.10054
Publikováno v:
Transactions of the American Mathematical Society. 368:3673-3694
We give a model theoretic proof that if there is a counterexample to Vaught’s conjecture there is a counterexample such that every model of cardinality א1 is maximal (strengthening a result of Hjorth’s). We also give a new proof of Harrington’
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::88a021b87720c8a314efc9f0703d85e8
https://doi.org/10.1090/tran/6572
https://doi.org/10.1090/tran/6572