# A preprint of Sela concerning the work of Kharlampovich-Miyasnikov

Yesterday, Z. Sela published a preprint in arXiv which claims that the solution of Olga Kharlampovich and Alexi Miyasnikov for the Tarski problem on decidablity of the first order theories of free groups and torsion free hyperbolic groups contains mistakes and so, that problem which was announced to be solved in 2006, is still an open problem. At this time, I am interested to know, which important theorems of Group theory, Model theory and Algebraic geometry over groups discovered in the period of 2006-2013 applied result of Kharlampovich-Miyasnikov.

Edit: An answer of Kharlampovich and Miyasnikov for the preprint of Sela is just published in arXiv. They explained briefly that there was no serious mistakes in their work, and many errors discovered by Sela are already have been corrected. See this link: http://arxiv.org/abs/1402.0482

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I guess that a related question that should be answered before is whether most of the mathematical community working on these topics also agree with Sela's point of view. –  boumol Jan 24 at 9:37
@boumol, MO is absolutely the wrong place to have that discussion - it's far too contentious. On the other hand, the original question is perfectly clear and straightforward - it asks for a list of results that rely on Olga and Alexei's work. –  HJRW Jan 24 at 11:40
@boumol I am not sure what point you want to make but see mathoverflow.net/questions/140459/… Of course not each and every request of this form will make a good question; for one thing because depending on the result it could be either 'too broad' or 'too localized' or something a long these lines, but certain ones should be reasonable. –  quid Jan 24 at 13:32
@boumol: No. The question is fundamentally 'List some consequences of the decidability of the elementary theory of free groups (or hyperbolic groups, if you prefer).' This is an OK question, completely independently of the status of Alexei and Olga's results. Note that the question is NOT: 'List some consequences of the undecidability of the elementary theory of free groups.' –  HJRW Jan 24 at 14:10
I also think that the title and question should be re-edited to remove contentious statements and in particular the phrase "(wrong!!!??)". The question should just ask what results depend on Olga and Alexei's work. –  Benjamin Steinberg Jan 24 at 16:54

Sela does not have an objective view of Kharlampovich, Myasnikov's work. We will post a paper dismissing his statements about "fatal mistakes". It just takes time. There are some typos and inessential errors that were fixed in later works. Sela himself has many such mistakes. The objects in the two works (Sela's and our work) are similar but not identical. They are not amenable to a crude direct interpretation; some of our statements would not be true if interpreted via a computer translation'' into his language (and vice versa). One example is
Sela's wrong Theorem 7 from his paper 6 on Diophantine Geometry. This theorem describes groups elementarily equivalent to a non-abelian free groups. Sela claims that our Theorem 41 is wrong too. But our theorem is stated using our concept of regular NTQ groups and is correct. This shows that regular NTQ groups are not completely identical to hyperbolic $\omega$-residually free towers. Many of his critical comments resulted from such an exact translation of our concepts into his language. Additional misrepresentations result from not remembering that some statement was made two pages before (such as that we only consider fundamental sequences satisfying first and second restrictions).