Description: The converse of the empty set is a function. (Contributed by AV, 7-Jan-2021)
Ref | Expression | ||
---|---|---|---|
Assertion | funcnv0 | ⊢ Fun ◡ ∅ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fun0 | ⊢ Fun ∅ | |
2 | cnv0 | ⊢ ◡ ∅ = ∅ | |
3 | 2 | funeqi | ⊢ ( Fun ◡ ∅ ↔ Fun ∅ ) |
4 | 1 3 | mpbir | ⊢ Fun ◡ ∅ |