\input zb-basic
\input zb-ioport
\iteman{io-port 06055332}
\itemau{Baklanova, N.A.}
\itemti{Minimal elements and minimal coverings in the Rogers semilattice of computable numberings in the hyperarithmetical hierarchy.}
\itemso{Vestn. Novosib. Gos. Univ., Ser. Mat. Mekh. Inform. 11, No. 3, 77-84 (2011).}
\itemab
Summary: We prove that the Rogers semilattice of any infinite $\Sigma_\omega$-computable family contains infinitely many minimal elements and each non-$0'$-universal numbering has infinitely many minimal covers.
\itemrv{~}
\itemcc{}
\itemut{numbering; Rogers semilattice; hyperarithmetical hierarchy; minimal element; minimal cover}
\itemli{}
\end