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Single Idea 18178

[filed under theme 6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / f. Zermelo numbers ]

Full Idea

For Zermelo the successor of n is {n} (rather than Von Neumann's successor, which is n U {n}).

Gist of Idea

For Zermelo the successor of n is {n} (rather than n U {n})

Source

report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Penelope Maddy - Naturalism in Mathematics I.2 n8

Book Ref

Maddy,Penelope: 'Naturalism in Mathematics' [OUP 2000], p.24


A Reaction

I could ask some naive questions about the comparison of these two, but I am too shy about revealing my ignorance.


The 21 ideas from Ernst Zermelo

Zermelo showed that the ZF axioms in 1930 were non-categorical [Zermelo, by Hallett,M]
Replacement was added when some advanced theorems seemed to need it [Zermelo, by Maddy]
The antinomy of endless advance and of completion is resolved in well-ordered transfinite numbers [Zermelo]
In ZF, the Burali-Forti Paradox proves that there is no set of all ordinals [Zermelo, by Hart,WD]
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]
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]
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]
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]
We should judge principles by the science, not science by some fixed principles [Zermelo]
Zermelo realised that Choice would facilitate the sort of 'counting' Cantor needed [Zermelo, by Lavine]
Zermelo made 'set' and 'member' undefined axioms [Zermelo, by Chihara]
For Zermelo's set theory the empty set is zero and the successor of each number is its unit set [Zermelo, by Blackburn]