Definitions
,
Results
,
Conjectures
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Set of symbols
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Alphabet
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Deduction system
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Theory
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Zermelo-Fraenkel set theory
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Set
Transitive set
Formulation 0
A
D11: Set
$X $ is a
transitive set
if and only if \begin{equation} \forall \, x \in X : \forall \, y \in x : y \in X \end{equation}
Formulation 1
A
D11: Set
$X $ is a
transitive set
if and only if \begin{equation} \forall \, x \in X : x \subseteq X \end{equation}
Formulation 2
A
D11: Set
$X $ is a
transitive set
if and only if \begin{equation} X \subseteq \mathcal{P}(X) \end{equation}
Child definitions
»
D672: Ordinal number
