\begin{definition}[Definition:Cardinality/Infinite]
Let $S$ be an infinite set.
The '''cardinality''' $\card S$ of $S$ can be indicated as:
:$\card S = \infty$
However, it needs to be noted that this just means that the cardinality of $S$ cannot be assigned a number $n \in \N$.
It means that $\card S$ is ''at least'' $\aleph_0$ (aleph null).
\end{definition}