Let $\mathbb{N}$ be the D225: Set of natural numbers such that

(1)	$E \subseteq \mathbb{N}$ is a D78: Subset

The lower basic natural number set density of $E$ is the D993: Real number \begin{equation} \liminf_{n \to \infty} \frac{|E \cap \{ 1, \dots, n \}|}{n} \end{equation}