$\emptyset$ and $\setdef{1, 2}$
Terms
| Term | This example | Why |
|---|---|---|
| subset | ✓ | $\emptyset$ is a subset of $\setdef{1, 2}$ because the empty set is a subset of every set. |
| proper subset | ✓ | $\emptyset$ is a proper subset of $\setdef{1, 2}$ because the empty set is a subset and $\emptyset \neq \setdef{1, 2}$. |
| element of | ✗ | $\emptyset$ is not an element of $\setdef{1, 2}$, because $\emptyset$ is an element only of sets that list it. |