Geodesic
Splitting of c.e. degrees and superlowness
Sibirskie èlektronnye matematičeskie izvestiâ, Tome 19 (2022) no. 2, pp. 578-585.

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In this paper, we show that for any superlow c.e. degrees $\mathbf{a}$ and $\mathbf{b}$ there exists a superlow c.e. degree $\mathbf{c}$ such that $\mathbf{c}\not=\mathbf{a}_0\cup\mathbf{b}_0$ for all c.e. degrees $\mathbf{a}_0\leqslant\mathbf{a}$, $\mathbf{b}_0\leqslant\mathbf{b}$. This provides one more elementary difference between the classes of low c.e. degrees and superlow c.e. degrees. We also prove that there is a c.e. degree that is not the supremum of any two superlow not necessarily c.e. degrees.
Keywords: low degree, superlow degree, jump-traceable set. 
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M. Kh. Faizrahmanov. Splitting of c.e. degrees and superlowness. Sibirskie èlektronnye matematičeskie izvestiâ, Tome 19 (2022) no. 2, pp. 578-585. http://geodesic.mathdoc.fr/item/SEMR_2022_19_2_a2/

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