Write out the following set by listing its elements between braces.

Question

Write out the following set by listing its elements between braces:

$\begin{align} \{X \subseteq \mathbb{N}: |X| \leq 1 \} &=\{\emptyset,\{1\},\{2\},\{3\},\ldots\}\end{align} $

Is my answer correct? My attempt at reading the left side: The set of elements $X$ contained in $\mathbb{N}$ such that $|X| \leq 1$.

Answer 1

Very right.

Since the cardinality of $\emptyset$ is less then 1. And the cardinality of any set contains two points at least is more than 1.

Answer 2

Yes, your answer is correct. ${}$