Definition:Basic Proposition

Let $$f : \mathbb{B}^k \to \mathbb{B}$$ be a boolean function, where:
 * $$\mathbb{B} = \left\{{0, 1}\right\}$$ is a boolean domain;
 * $$k\!$$ is a nonnegative integer.

A basic proposition is one of the projection functions $$\operatorname {pr}_j : \mathbb{B}^k \to \mathbb{B}$$, defined as follows:

Let $$X = \left({p_1, p_2, \ldots, p_k}\right) \in \mathbb{B}^k$$.

Then $$\operatorname {pr}_j \left({X}\right) = p_j$$.

That is, a basic proposition is one of the elements of the $k$-tuple $$\left({p_1, p_2, \ldots, p_k}\right)$$.