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We develop foundational aspects of stability theory in affine logic. On the one hand, we prove appropriate affine versions of many classical results, including definability of types, existence of non-forking extensions, and other…

Logic · Mathematics 2026-03-11 Itaï Ben Yaacov , Tomás Ibarlucía

We show that the ample degree of a stable theory with trivial forking is preserved when we consider the corresponding theory of belles paires, if it exists. This result also applies to the theory of $H$-structures of a trivial theory of…

Logic · Mathematics 2019-09-18 Enrique Casanovas , Amador Martin-Pizarro , Daniel Palacin

We observe that a simple condition suffices to describes non-forking independence over models in a stable theory. Under mild assumptions, this description can be extended to non-forking independence over algebraically closed subsets,…

Logic · Mathematics 2024-10-15 Amador Martin-Pizarro

We show that the theory of a non-degenerate representation of a C*-algebra A over a Hilbert space H is superstable. Also, we characterize forking, orthogonality and domination of types and show that the theory has weak elimination of…

Logic · Mathematics 2012-12-03 Camilo Argoty

We prove two results about generically stable types $p$ in arbitrary theories. The first, on existence of strong germs, generalizes results from D. Haskell, E. Hrushovski and D. Macpherson on stably dominated types. The second is an…

Logic · Mathematics 2012-10-23 Hans Adler , Enrique Casanovas , Anand Pillay

Let K be an algebraically bounded structure and T be its theory. If T is model complete, then the theory of K endowed with a derivation, denoted by $T^{\delta}$, has a model completion. Additionally, we prove that if the theory T is…

Logic · Mathematics 2024-11-14 Fornasiero Antongiulio , Terzo Giuseppina

We study thorn forking and rosiness in the context of continuous logic. We prove that the Urysohn sphere is rosy (with respect to finitary imaginaries), providing the first example of an essentially continuous unstable theory with a nice…

Logic · Mathematics 2009-11-19 Clifton Ealy , Isaac Goldbring

Forking is a central notion of model theory, generalizing linear independence in vector spaces and algebraic independence in fields. We develop the theory of forking in abstract, category-theoretic terms, for reasons both practical (we…

Logic · Mathematics 2019-02-19 Michael Lieberman , Jiří Rosický , Sebastien Vasey

We extend the notion of Heyting algebra to a notion of truth values algebra and prove that a theory is consistent if and only if it has a B-valued model for some non trivial truth values algebra B. A theory that has a B-valued model for all…

Logic in Computer Science · Computer Science 2023-05-15 Gilles Dowek

We prove a stability theorem for the elliptic Harnack inequality: if two weighted graphs are equivalent, then the elliptic Harnack inequality holds for harmonic functions with respect to one of the graphs if and only if it holds for…

Probability · Mathematics 2011-05-23 Richard F. Bass

We show that a derivator is stable if and only if homotopy finite limits and homotopy finite colimits commute, if and only if homotopy finite limit functors have right adjoints, and if and only if homotopy finite colimit functors have left…

Algebraic Topology · Mathematics 2021-07-14 Moritz Groth , Mike Shulman

We provide a partial answer to a question asked independently by Kim and d'Elb\'ee and show that, under the assumption of the stable Kim-forking conjecture, every $\mathrm{NSOP}_1$ rosy theory must be simple. We also prove that the theory…

Logic · Mathematics 2026-01-14 Alberto Miguel-Gómez

We characterize stable T for which the model completion of T_{aut} is stable (i.e., every completion is). Then we prove that ``some completion is stable'' is different and we characterize it. Finally we show that if T is stable, T_{aut} has…

Logic · Mathematics 2007-05-23 Saharon Shelah

We define weak stable Kim-forking, a notion that generalizes stable forking to the context of NSOP1 theories. We adapt some of the known results on stable forking to this context.

Logic · Mathematics 2025-11-03 Yvon Bossut

We prove that there are energetically stable bimetric theories. These theories satisfies a positive energy theorem. We construct a model example.

General Relativity and Quantum Cosmology · Physics 2014-07-23 Idan Talshir

We show that certain tilting results for quivers are formal consequences of stability, and as such are part of a formal calculus available in any abstract stable homotopy theory. Thus these results are for example valid over arbitrary…

Algebraic Topology · Mathematics 2016-03-02 Moritz Groth , Jan Stovicek

Let T be a complete first order theory in a countable relational language L . We assume relation symbols have been added to make each formula equivalent to a predicate. Adjoin a new unary function symbol sigma to obtain the language…

Logic · Mathematics 2007-05-23 John Baldwin , Saharon Shelah

In this paper we explore the representation property over sets. This property generalizes constructibility, however is weak enough to enable us to prove that the class of theories $T$ whose models are representable is exactly the class of…

Logic · Mathematics 2009-06-18 Moran Cohen , Saharon Shelah

We prove that if $T$ is a complete theory with weak elimination of imaginaries, then there is an explicit bijection between strict independence relations for $T$ and strict independence relations for $T^{\text{eq}}$. We use this observation…

Logic · Mathematics 2018-09-12 Gabriel Conant

It is a well known empirical observation that natural axiomatic theories are pre-well-ordered by consistency strength. For any natural theory $T$, the next strongest natural theory is $T+\mathsf{Con}_T$. We formulate and prove a statement…

Logic · Mathematics 2019-10-29 James Walsh
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