Description: Example for df-eprel . Example by David A. Wheeler. (Contributed by Mario Carneiro, 18-Jun-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ex-eprel | ⊢ 5 E { 1 , 5 } |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 5nn | ⊢ 5 ∈ ℕ | |
| 2 | 1 | elexi | ⊢ 5 ∈ V |
| 3 | 2 | prid2 | ⊢ 5 ∈ { 1 , 5 } |
| 4 | prex | ⊢ { 1 , 5 } ∈ V | |
| 5 | 4 | epeli | ⊢ ( 5 E { 1 , 5 } ↔ 5 ∈ { 1 , 5 } ) |
| 6 | 3 5 | mpbir | ⊢ 5 E { 1 , 5 } |