Question

If $\varphi$ denotes the empty set, then which of the folowing is correct

• A. $\varphi \in \varphi$
• B. $\varphi \in \left\{\varphi \right\}$
• C. $\left\{\varphi \right\}\in \left\{\varphi \right\}$
• D. $0\in \varphi$

Answer 1

The correct option is B $\varphi \in \left\{\varphi \right\}$

Option $\left(a\right)$
$\varphi$ is not the element of $\varphi$. So, it is wrong.

Option $\left(b\right)$
$\varphi$ is an element of $\left\{\varphi \right\}$. So, it is correct.

Option $\left(c\right)$
$\left\{\varphi \right\}$ is not the element of $\left\{\varphi \right\}$. So, it is wrong.

Option $\left(d\right)$
$0$ is not the element of $\varphi$. So it is wrong.