The Galerkin Analysis for the Random Periodic Solution of Semilinear Stochastic Evolution Equations
Wu, Y Yuan, C Journal of Theoretical Probability volume 36 issue 1 (25 Jan 2023)
The developmental basis of fingerprint pattern formation and variation
Glover, J Sudderick, Z Shih, B Bartho-Samblas, C Charlton, L Krause, A Anderson, C Riddell, J Balic, A Li, J Klika, V Woolley, T Gaffney, E Corsinotti, A Anderson, R Johnston, L Brown, S Wang, S Chen, Y Crichton, M Headon, D Cell volume 186 issue 5 940-956 (09 Feb 2023)
Entropy functions for accelerating black holes
Boido, A Gauntlett, J Martelli, D Sparks, J Physical Review Letters volume 130 (28 Feb 2023)
Efficient Risk Estimation for the Credit Valuation Adjustment
Giles, M Haji-Ali, A Spence, J (14 Jan 2023)
Hyperbolically embedded subgroups and quasi-isometries of pairs
Hughes, S Martínez-Pedroza, E Canadian Mathematical Bulletin 1-16 (10 Jan 2023)
Thu, 02 Feb 2023
17:00
L3

Geometric Stability Theory and the Classification of Unstable Structures

Scott Mutchnik
(University of California, Berkeley)
Abstract

The equivalence of NSOP${}_1$ and NSOP${}_3$, two model-theoretic complexity properties, remains open, and both the classes NSOP${}_1$ and NSOP${}_3$ are more complex than even the simple unstable theories. And yet, it turns out that classical geometric stability theory, in particular the group configuration theorem of Hrushovski (1992), is capable of controlling classification theory on either side of the NSOP${}_1$-SOP${}_3$ dichotomy, via the expansion of stable theories by generic predicates and equivalence relations. This allows us to construct new examples of strictly NSOP${}_1$ theories. We introduce generic expansions corresponding, though universal axioms, to definable relations in the underlying theory, and discuss the existence of model companions for some of these expansions. In the case where the defining relation in the underlying theory $T$ is a ternary relation $R(x, y, z)$ coming from a surface in 3-space, we give a surprising application of the group configuration theorem to classifying the corresponding generic expansion $T^R$. Namely, when $T$ is weakly minimal and eliminates the quantifier $\exists^{\infty}$, $T^R$ is strictly NSOP${}_4$ and TP${}_2$ exactly when $R$ comes from the graph of a type-definable group operation; otherwise, depending on whether the expansion is by a generic predicate or a generic equivalence relation, it is simple or NSOP${}_1$.

Counting graphic sequences via integrated random walks
Balister, P Donderwinkel, S Groenland, C Johnston, T Scott, A (17 Jan 2023) http://arxiv.org/abs/2301.07022v2
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