scholarly journals Dichotomy theorems for families of non-cofinal essential complexity

2017 ◽  
Vol 304 ◽  
pp. 285-299 ◽  
Author(s):  
John D. Clemens ◽  
Dominique Lecomte ◽  
Benjamin D. Miller
Keyword(s):  
2018 ◽  
Vol 40 (6) ◽  
pp. 1715-1728
Author(s):  
TAO YU ◽  
XIAOMIN ZHOU

Let $\unicode[STIX]{x1D70B}:(X,T)\rightarrow (Y,S)$ be an extension between minimal systems; we consider its relative sensitivity. We obtain that $\unicode[STIX]{x1D70B}$ is relatively $n$-sensitive if and only if the relative $n$-regionally proximal relation contains a point whose coordinates are distinct; and the structure of $\unicode[STIX]{x1D70B}$ which is relatively $n$-sensitive but not relatively $(n+1)$-sensitive is determined. Let ${\mathcal{F}}_{t}$ be the families consisting of thick sets. We introduce notions of relative block ${\mathcal{F}}_{t}$-sensitivity and relatively strong ${\mathcal{F}}_{t}$-sensitivity. Let $\unicode[STIX]{x1D70B}:(X,T)\rightarrow (Y,S)$ be an extension between minimal systems. Then the following Auslander–Yorke type dichotomy theorems are obtained: (1) $\unicode[STIX]{x1D70B}$ is either relatively block ${\mathcal{F}}_{t}$-sensitive or $\unicode[STIX]{x1D719}:(X,T)\rightarrow (X_{\text{eq}}^{\unicode[STIX]{x1D70B}},T_{\text{eq}})$ is a proximal extension where $(X_{\text{eq}}^{\unicode[STIX]{x1D70B}},T_{\text{eq}})\rightarrow (Y,S)$ is the maximal equicontinuous factor of $\unicode[STIX]{x1D70B}$. (2) $\unicode[STIX]{x1D70B}$ is either relatively strongly ${\mathcal{F}}_{t}$-sensitive or $\unicode[STIX]{x1D719}:(X,T)\rightarrow (X_{d}^{\unicode[STIX]{x1D70B}},T_{d})$ is a proximal extension where $(X_{d}^{\unicode[STIX]{x1D70B}},T_{d})\rightarrow (Y,S)$ is the maximal distal factor of $\unicode[STIX]{x1D70B}$.


2012 ◽  
Vol 86 (1) ◽  
pp. 235-258 ◽  
Author(s):  
N. J. Laustsen ◽  
E. Odell ◽  
Th. Schlumprecht ◽  
A. Zsák

2016 ◽  
Vol 16 (01) ◽  
pp. 1650001 ◽  
Author(s):  
Franck Benoist ◽  
Elisabeth Bouscaren ◽  
Anand Pillay

We give a reduction of the function field Mordell–Lang conjecture to the function field Manin–Mumford conjecture, for abelian varieties, in all characteristics, via model theory, but avoiding recourse to the dichotomy theorems for (generalized) Zariski geometries. Additional ingredients include the “Theorem of the Kernel”, and a result of Wagner on commutative groups of finite Morley rank without proper infinite definable subgroups. In positive characteristic, where the main interest lies, there is one more crucial ingredient: “quantifier-elimination” for the corresponding [Formula: see text] where [Formula: see text] is a saturated separably closed field.


2002 ◽  
Vol 02 (01) ◽  
pp. 113-144 ◽  
Author(s):  
GREG HJORTH

We show that every ℵα(α<ω1) can be characterized by the Scott sentence of some countable model; moreover there is a countable structure whose Scott sentence characterizes ℵ1but whose automorphism group fails the topological Vaught conjecture on analytic sets.We obtain some partial information on Ulm type dichotomy theorems for the automorphism group of Knight's model.


2001 ◽  
Vol 66 (2) ◽  
pp. 902-922 ◽  
Author(s):  
Su Gao

AbstractStrengthening known instances of Vaught Conjecture, we prove the Glimm-Effros dichotomy theorems for countable linear orderings and for simple trees. Corollaries of the theorems answer some open questions of Friedman and Stanley in an Lω1ω-interpretability theory. We also give a survey of this theory.


2012 ◽  
Vol 18 (4) ◽  
pp. 554-575 ◽  
Author(s):  
Benjamin D. Miller

AbstractWe sketch the ideas behind the use of chromatic numbers in establishing descriptive set-theoretic dichotomy theorems.


Sign in / Sign up

Export Citation Format

Share Document