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15 votes
1 answer
1k views

Where did Zermelo first model the natural numbers by iterates of the singleton operator, and have the definitions been compared by himself?

E. Zermelo is widely said to have modelled the (axioms of the) natural numbers by iterating the singleton operation $\{\cdot\}\colon \mathsf{Set}\rightarrow\mathsf{Set}$, $S\mapsto\{S\}$, whence the ...
Peter Heinig's user avatar
  • 6,051
17 votes
2 answers
2k views

Why did Gödel name his constructible universe $L$?

It seems like Gödel didn't use the letter $L$ for his model before his book "The Consistency of the Axiom of Choice and of the Generalized Continuum-Hypothesis with the Axioms of Set Theory", which is ...
Dan Saattrup Nielsen's user avatar
22 votes
2 answers
3k views

Where are Georg Cantor's Original Manuscripts?

Georg Cantor is famous for introducing transfinite numbers and set theory. A main part of his mathematical point of view about this new type of "numbers" and this new "realm of mathematics" cannot be ...
user45421's user avatar
  • 229
3 votes
0 answers
342 views

A Question Regarding Boolean-valued Models

What were the intuitions motivating the creation (or discovery, if you will) of Boolean-valued models? I have searched for the Scott-Solovay paper on the subject, but to no avail. There also seems to ...
Thomas Benjamin's user avatar
13 votes
1 answer
2k views

Hausdorff and Naive Set Theory

Erhard Scholz, in his article "Felix Hausdorff and the Hausdorff edition" writes the following: "Hausdorff considered the contemporary attempts to secure axiomatic foundations for set theory as ...
Thomas Benjamin's user avatar
9 votes
1 answer
918 views

What is the etymology of zero-sharp?

I have wondered for a while what gave rise to the notation $0^\sharp$. According to wikipedia this is due to Solovay in 1967, but (perhaps unsurprisingly) there's no discussion of why that notation ...
Chris Le Sueur's user avatar