I love SAT solver papers, always interesting to see auxiliary variable techniques, since those aren't really listed anywhere central

here for example, instead of saying {f(x,y,z)==g(x,y,z)}, authors instead make variable group a_w:=(f(x,y,z)=w||g(x,y,z)=w), and then apply "at most 1" to it. Can't be unequal if both functions only can have 1 result in total

this adds an index to iterate over, but separates internal subexpressions of f() and g(), removing 2 indixes (in this problem) and thus dropping whole power of n of clauses

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what I don't get is that they aren't searching Tarski's problem per se, but for one specific solution to it (one identity that isn't resulting from given). I'd totally look for arithmetic models that violate expectations in other ways than Wilkie

The lower bound had already been established in prior work: https://zenodo.org/records/18568303

They address the following concern of Zhang (2005), which contained prior work involving similar techniques:

> […] Of course, this conclusion is not proved mathematically. It is possible that the programs have some bugs, or the user (myself made some errors.

They address it as follows:

> We address this [… through] ChatGPT 5.5 Pro, through Codex, to automatically generate a Lean formalization that we then checked ourselves to confirm the statements and definitions indeed match their expected semantics. This process took multiple iterations and discussions with the model over several days, and generated over 10,000 lines of code.

This is extremely unconvincing. Manual review of 10,000 lines of AI generated code is a terrifying prospect. I’m sure the result is correct, however I am deeply uncomfortable with this being mankind’s new mathematical process. Similar concerns have been expressed since the days of the 4 color theorem, but this feels different. Perhaps it is just new.

>in a nutshell, it defines an executable function encode that takes a natural number n ≥ 5 and emits a CNF formula, which is byte-for-byte equal to the output of our Python encoding

The phrase “byte-for-byte equal” makes my eye twitch these days.

Why is subtraction not part of the algebra? It’s certainly familiar to every high school math student. This omission allows the counterexample, so the reveal is a bit of a disappointment IMHO.

Isn't the underlying question proved impossible by Godel's incompletness theorem?

I thought SAT like the high school admissions test