Paper 1, Section II, F
(a) Define a register machine, a sequence of instructions for a register machine and a partial computable function. How do we encode a register machine?
(b) What is a partial recursive function? Show that a partial computable function is partial recursive. [You may assume that for a given machine with a given number of inputs, the function outputting its state in terms of the inputs and the time is recursive.]
(c) (i) Let be the partial function defined as follows: if codes a register machine and the ensuing partial function is defined at , set . Otherwise set . Is a partial computable function?
(ii) Let be the partial function defined as follows: if codes a register machine and the ensuing partial function is defined at , set . Otherwise, set if is odd and let be undefined if is even. Is a partial computable function?