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It is known for a while now that $\frak p=t$, as a result of Malliaris-Shelah. The original paper draws from model theoretic methods.

I've heard rumors that there was a proof which was purely set theoretic, and indeed much shorter than the original.

Does anyone know who wrote it, and whether or not it appears online/in print, and if so, is there an available link/reference?

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    $\begingroup$ For the set-theoretically ignorant among us: shelah.logic.at/files/998.pdf. $\endgroup$ Commented May 25, 2014 at 18:25
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    $\begingroup$ I've heard Juris Steprans has a manuscript with such a proof. Not so sure that it's "purely set theoretic" though, I've heard it's mostly a translation of sorts into the set-theoretic language (so someone without a lot of knowledge in model theory can understand it), but using the same underlying ideas. $\endgroup$ Commented May 25, 2014 at 18:49
  • $\begingroup$ Dear Asaf, I attached a paper by Steprans, which gives a proof of p=t by set theoretic methods. $\endgroup$ Commented May 26, 2014 at 2:44
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    $\begingroup$ David Fremlin recently uploaded a note on this result based on (what I think is) the note by Juris Steprans that is mentioned above: essex.ac.uk/maths/people/fremlin/n14528.pdf $\endgroup$
    – user3462
    Commented Jul 9, 2014 at 1:00

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One reference is given above by Inamdar that can be found here:

$\frak p=t$, following Malliaris-Shelah and Steprans (Internet Archive).

Also there is another reference where not only it gives a proof of the $\frak p=t$ based on Steprans ideas, but it also gives in a very nice way some other results proved by Malliaris-Shelah:

Ultraproducts of finite partial orders and some of their applications in model theory and set theory (Internet Archive)

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While not short, A Measure Theoretic Proof of $\mathfrak p=\mathfrak t$ gives a proof that does not rely on model theoretic or proof theoretic techniques. Since the measure theory is basic, Kunen's text is sufficient background. (It in fact establishes a stronger result which implies the equality.)

To my knowledge, all of the other proofs are distillations of the original Malliaris--Shelah proof.

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