Definition:Basic Primitive Recursive Function/Projection Function

Definition
The projection functions $\pr_j^k: \N^k \to \N$ are basic primitive recursive functions, defined as:
 * $\forall \tuple {n_1, n_2, \ldots, n_k} \in \N^k: \map {\pr_j^k} {n_1, n_2, \ldots, n_k} = n_j$

where $j \in \closedint 1 k$.

They are each URM computable by a single-instruction URM program.