Primitive recursion
= Primitive recursion
{wiki}
From $g:\mathbb N^k\to\mathbb N$ and $h:\mathbb N^{k+2}\to\mathbb N$, primitive recursion defines
$$
f(\mathbf x,0)=g(\mathbf x),
\qquad
f(\mathbf x,n+1)=h(\mathbf x,n,f(\mathbf x,n)).
$$
= Primitive recursion
{wiki}
From $g:\mathbb N^k\to\mathbb N$ and $h:\mathbb N^{k+2}\to\mathbb N$, primitive recursion defines
$$
f(\mathbf x,0)=g(\mathbf x),
\qquad
f(\mathbf x,n+1)=h(\mathbf x,n,f(\mathbf x,n)).
$$