Abstract: In computability theory, theorems proved are always accompanied with new techniques.- Developing new techniques is kind of byproduct when problems are solved.   In Friedberg-Muchinic’s solution to Post’s problem, finite priority arguments is introduced. Lachlan’s nonsplitting theorem shows that Sacks splitting and Sacks density cannot be combined. In this work, Lachlan introduced the 0’’’ method, which was considered as a monstrous method in the 1980s. Sacks forcing was introduced when he showed that 0’ bounds a minimal degree [Spector’s original construction cannot be implemented below 0’]. Yates’ full approximation method was developed when he shows that every nonzero c.e. degree bounds a minimal degree.