Description: A pair containing a set is not empty. (Contributed by NM, 9-Apr-1994)
Ref | Expression | ||
---|---|---|---|
Hypothesis | prnz.1 | ⊢ 𝐴 ∈ V | |
Assertion | prnz | ⊢ { 𝐴 , 𝐵 } ≠ ∅ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | prnz.1 | ⊢ 𝐴 ∈ V | |
2 | 1 | prid1 | ⊢ 𝐴 ∈ { 𝐴 , 𝐵 } |
3 | 2 | ne0ii | ⊢ { 𝐴 , 𝐵 } ≠ ∅ |