Definition:Basic Primitive Recursive Function/Identity Function

Definition
The identity function $I_\N: \N \to \N$ is a basic primitive recursive function, defined as:
 * $\forall n \in \N: I_\N \left({n}\right) = n$

Note that this is an implementation of the projection function:
 * $\operatorname{pr}^1_1: \N \to \N: \operatorname{pr}^1_1 \left({\left({n_1}\right)}\right) = n_1$

It is URM computable by a single-instruction URM program.