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Single Idea 10870

[filed under theme 4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets ]

Full Idea

Zermelo-Fraenkel axioms: Existence (at least one set); Extension (same elements, same set); Specification (a condition creates a new set); Pairing (two sets make a set); Unions; Powers (all subsets make a set); Infinity (set of successors); Choice

Gist of Idea

ZFC: Existence, Extension, Specification, Pairing, Unions, Powers, Infinity, Choice

Source

report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Brian Clegg - Infinity: Quest to Think the Unthinkable Ch.15

Book Ref

Clegg,Brian: 'Infinity' [Robinson 2003], p.205


The 14 ideas from 'Investigations in the Foundations of Set Theory I'

Not every predicate has an extension, but Separation picks the members that satisfy a predicate [Zermelo, by Hart,WD]
Zermelo introduced Pairing in 1930, and it seems fairly obvious [Zermelo, by Maddy]
Zermelo used Foundation to block paradox, but then decided that only Separation was needed [Zermelo, by Maddy]
The Axiom of Separation requires set generation up to one step back from contradiction [Zermelo, by Maddy]
In ZF, the Burali-Forti Paradox proves that there is no set of all ordinals [Zermelo, by Hart,WD]
For Zermelo the successor of n is {n} (rather than n U {n}) [Zermelo, by Maddy]
Zermelo believed, and Von Neumann seemed to confirm, that numbers are sets [Zermelo, by Maddy]
Different versions of set theory result in different underlying structures for numbers [Zermelo, by Brown,JR]
Predicative definitions are acceptable in mathematics if they distinguish objects, rather than creating them? [Zermelo, by Lavine]
ZFC: Existence, Extension, Specification, Pairing, Unions, Powers, Infinity, Choice [Zermelo, by Clegg]
Zermelo published his axioms in 1908, to secure a controversial proof [Zermelo, by Maddy]
Set theory can be reduced to a few definitions and seven independent axioms [Zermelo]
We take set theory as given, and retain everything valuable, while avoiding contradictions [Zermelo]
Set theory investigates number, order and function, showing logical foundations for mathematics [Zermelo]