The authors show that this is done easily within any of the available base sets (1, 2, or 3) (an example can be found at μ operator ). However, the reader needs to be cautioned that, even though the μ operator is easily created by the base instruction set doesn't mean that an arbitrary partial recursive function can be easily created with a base model -- Turing equivalence and partial recursive functions imply an "unbounded" μ operator, one that can scurry to the ends of the register chain ad infinitum searching for its goal. The problem is: registers must be called out explicily by number/name e.g. INC (47,528) and DEC (39,347) and this will exhaust the finite state machine's TABLE of instructions. No matter how "big" the finite state machine is, we can find a function that uses a "bigger" number of registers.