Description: Even the monoid of endofunctions on the empty set is actually a monoid. (Contributed by AV, 31-Jan-2024)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | efmnd0nmnd | ⊢ ( EndoFMnd ‘ ∅ ) ∈ Mnd |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0ex | ⊢ ∅ ∈ V | |
| 2 | eqid | ⊢ ( EndoFMnd ‘ ∅ ) = ( EndoFMnd ‘ ∅ ) | |
| 3 | 2 | efmndmnd | ⊢ ( ∅ ∈ V → ( EndoFMnd ‘ ∅ ) ∈ Mnd ) |
| 4 | 1 3 | ax-mp | ⊢ ( EndoFMnd ‘ ∅ ) ∈ Mnd |