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In set theory, Zermelo–Fraenkel set theory, named after mathematicians Ernst Zermelo and Abraham Fraenkel, is an axiomatic system that was proposed in the early twentieth century in order to formulate a theory of sets free of paradoxes such as Russell's paradox. Today, Zermelo–Fraenkel set theory, with the historically controversial axiom of choice (AC)…
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set zfc axiom axioms theory displaystyle sets choice zermelo fraenkel exists existence one zf also universe schema union consistency classes
| Subject | Predicate | Object | Confidence | Src |
|---|---|---|---|---|
| Russell's paradox | instance of | is an axiomatic system that was proposed in the early twentieth century in order to formulate a theory of sets free of paradoxes | 0.80 | text |
| ZFC cannot be proved within the theory itself | instance of | The consistency of a theory | 0.80 | text |
| as shown by Gödel's second incompleteness theorem | instance of | The consistency of a theory | 0.80 | text |
| Von Neumann | instance of | and that the powerset of x will be added at the next stage after α.The picture of the universe of sets stratified into the cumulative hierarchy is characteristic of ZFC and rela… | 0.80 | text |
| New Foundations.It is possible to change the definition of V so that at each stage | instance of | The cumulative hierarchy is not compatible with other set theories | 0.80 | text |
| instead of adding all the subsets of the union of the previous stages | instance of | The cumulative hierarchy is not compatible with other set theories | 0.80 | text |
| subsets are only added if they are definable in a certain sense | instance of | The cumulative hierarchy is not compatible with other set theories | 0.80 | text |
| proper classes.Many mathematical theorems can be proven in much weaker systems than ZFC | instance of | as well as for its failure to capture objects | 0.80 | text |
| such as Peano arithmetic | instance of | as well as for its failure to capture objects | 0.80 | text |
| second-order arithmetic | instance of | as well as for its failure to capture objects | 0.80 | text |
| Martin's axiom or large cardinal axioms to ZFC | instance of | Some of these conjectures are provable with the addition of axioms | 0.80 | text |
| Zermelo–Fraenkel set theory | related to External links | Axioms | 0.60 | section |
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