Description: An example for the membership relation. (Contributed by AV, 19-Jun-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 0sn0ep | ⊢ ∅ E { ∅ } |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0ex | ⊢ ∅ ∈ V | |
| 2 | 1 | snid | ⊢ ∅ ∈ { ∅ } |
| 3 | snex | ⊢ { ∅ } ∈ V | |
| 4 | 3 | epeli | ⊢ ( ∅ E { ∅ } ↔ ∅ ∈ { ∅ } ) |
| 5 | 2 4 | mpbir | ⊢ ∅ E { ∅ } |