18.404J/6.840J The Theory of Computation(Fall 2020, MIT OCW). Instructor: Prof. Michael Sipser. This course emphasizes computability and computational complexity theory. Topics include regular and context-free languages, decidable and undecidable problems, reducibility, recursive function theory, time and space measures on computation, completeness, hierarchy theorems, inherently complex problems, oracles, probabilistic computation, and interactive proof systems.
(from ocw.mit.edu)
Lecture 09 - Reducibility
Quickly reviewed last lecture. Discussed the reducibility method to prove undecidability and T-unrecognizability. Defined mapping reducibility as a type of reducibility. Showed that ETM is undecidable and T-unrecognizable; EQTM and EQTM are T-unrecognizable.