Projection Function (Recursion)

computation

Definition

Projection Function (Recursion)

$$P_i^k:P_i^k(x_1,\dots ,x_k)=x_i(1\le i\le k)$$

Examples:

• $P_1^3\equiv [f(x,y,z)=x]$
• $(P_2^2,P_1^2)\equiv [f(x,y)=(y,x)]$