论文部分内容阅读
It will be proved that given any noncappable r.e. degree a there are r.e.degrees a0 and a1 such that a0,a1(≤)a and [a0∪a1] is not local distributive,i.e.,there is an r.e.degree c such that [c](≤)[a0∪a1] and for any [ui](≤)[ai] and i=0,1,[c]≠[u0]∨[u1]where R/M is the quotient of the recursively enumerable degrees modulo the cappable degrees. Therefore,R/M is not distributive.