Post asked 60 years ago whether it is possible to have an enumerable set which is neither computable, nor as difficult as the halting problem. The solution of Post's problem in the sixties, and the earlier attempts introduced several interesting ideas and techniques to computability, some of which have made there way into modern computer science research. This talk will concentrate on the idea of using immunity to solve Post's problem, and trace the history of that idea in computability. I will review notions from computability as necessary. Knowing the notion of a Turing machine, and the recursion theorem should be enough to follow most of the talk.
There is no paper for this talk, but I am planning to cover some material from my immunity paper.