Ingrassia proved that the p-generic Turing degrees are dense in the r.e. degrees and Ding De-cheng proved that the non-p-generic degrees are dense in the r.e. degrees too. But, do these two kinds of degrees have the s...Ingrassia proved that the p-generic Turing degrees are dense in the r.e. degrees and Ding De-cheng proved that the non-p-generic degrees are dense in the r.e. degrees too. But, do these two kinds of degrees have the same frequency of occurrency in every part of the r.e. degrees? In this note we give a negative answer.展开更多
It has been proved by the author that every p-generic degree is nonbranching.In this paper we construct an r.e.degree which is strongly nonbranching and non-p-generic.It means that the class of nonbranching degrees do...It has been proved by the author that every p-generic degree is nonbranching.In this paper we construct an r.e.degree which is strongly nonbranching and non-p-generic.It means that the class of nonbranching degrees does not coincide with the class of p-generic degrees.展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘Ingrassia proved that the p-generic Turing degrees are dense in the r.e. degrees and Ding De-cheng proved that the non-p-generic degrees are dense in the r.e. degrees too. But, do these two kinds of degrees have the same frequency of occurrency in every part of the r.e. degrees? In this note we give a negative answer.
基金Supported by a grant of the Stiftung Volkswagenwerk National Science Foundation of China.
文摘It has been proved by the author that every p-generic degree is nonbranching.In this paper we construct an r.e.degree which is strongly nonbranching and non-p-generic.It means that the class of nonbranching degrees does not coincide with the class of p-generic degrees.
