11.3 Universal Machines
11.3 Universal Machines A universal Turing machine is a Turing machine that can simulate other Turing machines. This is one of the most important ideas in computability theory. It means that computation can be represented as data. A machine can be written down, encoded as a string, and given as input to another machine. In ordinary programming terms, a universal machine is like an interpreter. It receives two things: $$...