Timeline for What is Gödel's pairing function on ordinals?
Current License: CC BY-SA 3.0
6 events
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| Nov 11, 2012 at 19:17 | history | edited | Andrés E. Caicedo | CC BY-SA 3.0 |
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| Nov 11, 2012 at 18:10 | comment | added | Andrés E. Caicedo | Thanks Asaf and Joel! I didn't expect this argument to go back this far. | |
| Nov 11, 2012 at 18:09 | comment | added | Andrés E. Caicedo | Hmm... the attribution seems right. I have not seen Hessenberg's book, but Oliver Deiser's "Einführung in die Mengenlehre" describes Hessenberg's argument in page 301, and it is reasonably close to the one above. | |
| Nov 11, 2012 at 18:09 | comment | added | Joel David Hamkins | It is basically the same idea as the Hessenberg (commutative) addition operation on ordinals. For that, you sort the two Cantor normal forms to have the same terms, as here, and just add coordinate-wise. The twist for coding is not to just add the similar terms, but also to apply a natural number pairing function also. | |
| Nov 11, 2012 at 17:02 | comment | added | Asaf Karagila♦ | In the comments to Joel's answer I wrote that Jech attributes this proof to Hessenberg. | |
| Nov 11, 2012 at 16:55 | history | answered | Andrés E. Caicedo | CC BY-SA 3.0 |