Description: Natural numbers are finite sets. (Contributed by Stefan O'Rear, 21-Mar-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | nnfi | |- ( A e. _om -> A e. Fin ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | onfin2 | |- _om = ( On i^i Fin ) |
|
2 | inss2 | |- ( On i^i Fin ) C_ Fin |
|
3 | 1 2 | eqsstri | |- _om C_ Fin |
4 | 3 | sseli | |- ( A e. _om -> A e. Fin ) |