There is no plus-capping degree
The authors answer a question of Per Lindström. It is proved that there is no ``plus-capping'' degree, i.e. that for any incomplete r.e. degree \({\mathbf w}\), there is an incomplete r.e. degree \({\mathbf a}> {\mathbf w}\) such that there is no r.e. degree \({\mathbf v}> {\mathbf w}\) with \({\mathbf a}\cap {\mathbf v}= {\mathbf w}\).
scientific article; zbMATH DE number 579321