The extendibility of relatively capping degrees under the weak truth table reducibility (Q1334032)

The authors continue to study the now very popular notion of relative extendibility of capping degrees. They prove that for any wtt-degrees \(a\), \(b\), \(d\) such that \(d= a\cap b\), \(a| b\), there exist wtt-degrees \(d_ 1\) and \(d_ 2\), \(d_ 1> a\), \(d_ 2> b\), such that \(d_ 1\cap d_ 2= d\). In the proof, the Sacks coding strategy is used.