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I'm reading about autoreducibility, which is the following notion:

A set $L$ is autoreducible if there is a polynomial-time oracle Turing machine $M$ that accepts $L$ using $L$ as an oracle, with the caveat that $M(x)$ may not query whether $x \in L$.

I encountered some results that are confusing me. In Using autoreducibility to separate complexity classes, Buhrman et al. showed that every polynomial-time Turing-complete set for EXPSPACE is autoreducible (Theorem 4.1). In Diagonalization, a survey by Fortnow, there is a theorem stating that if every Turing-complete set for EXPSPACE is autoreducible then $NL \neq NP$ (Theorem 3.1). So using both theorems together, we have $NP \neq NL$! I want to know where is my fault.

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The result from Buhrman et al. is about EXP rather than EXPSPACE.

Note that Theorem 3.1 from Fortnow's survey is taken from the very same paper of Buhrman et al.

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  • $\begingroup$ Thank you so much. I didn't knew about new version. $\endgroup$ – Mohsen Ghorbani Jul 21 at 5:54

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