[FOM] ZF[n] and (n+2)-order arithmetic

Ali Enayat ali.enayat at gmail.com
Fri Sep 9 18:37:19 EDT 2011

1. In my previous posting (Sep 8) on the same topic, I neglected to
include a link to an FOM posting of mine that briefly contrasts the
two concepts of mutual interpretability and bi-interpretability, here
it is:


2. The negation of Infinity was inadvertently omitted in statements
(A) and (B) of part 4 of my posting of Sep 8; in particular, the
system of set theory that is bi-interpretable with PA is:

ZF\{Infinity} + the negation of Infinity + Every set has a transitive closure.

Best regards,

Ali Enayal

---------- Forwarded message ----------
From: Ali Enayat <ali.enayat at gmail.com>
Date: Fri, Sep 9, 2011 at 3:32 PM
Subject: An addendum to my FOM posting
To: colin.mclarty at case.edu

Hello Colin,

I have posted a reply to your recent query on FOM that is now
available on the FOM archines.

In my reply, I provided a link to an earlier FOM posting of mine (in
which I discuss the bi-interpretability of second order arithmetic and
a brand of set theory). I should have also included the link below to
another FOM posting discussing the difference between mutual
interpretability and bi-interpretability.


Best regards,


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