This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.
Metamath Proof Explorer
Description: The index of the slot for the group operation in an extensible structure
is a positive integer. (Contributed by AV, 31-Oct-2024)
|
|
Ref |
Expression |
|
Assertion |
tsetndxnn |
⊢ ( TopSet ‘ ndx ) ∈ ℕ |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
tsetndx |
⊢ ( TopSet ‘ ndx ) = 9 |
| 2 |
|
9nn |
⊢ 9 ∈ ℕ |
| 3 |
1 2
|
eqeltri |
⊢ ( TopSet ‘ ndx ) ∈ ℕ |