From the author’s abstract:
In this paper we will give exact recursion-theoretical characterization of the computational power of . . . fuzzy Turing machines. Namely, we will show that fuzzy languages accepted by these machines with a computable t-norm correspond exactly to the union &Sgr;10 ∪ &Pgr;10 of recursively enumerable languages and their complements.
Unfortunately, there seems to be a mistake in the proof of Theorem 3.2 in this paper. I am only able to conclude from the proof that the languages accepted by fuzzy Turing machines are included in the Boolean closure of recursively enumerable languages. (This follows straightforwardly from the definition of a fuzzy Turing machine.) Hence, the &Sgr;10 ∪ &Pgr;10 characterization mentioned in the abstract fails.
