Description: For any ordinal, there is always a larger ordinal. (Contributed by RP, 1-Feb-2025)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | onexgt | |- ( A e. On -> E. x e. On A e. x ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | onsuc | |- ( A e. On -> suc A e. On ) | |
| 2 | sucidg | |- ( A e. On -> A e. suc A ) | |
| 3 | eleq2 | |- ( x = suc A -> ( A e. x <-> A e. suc A ) ) | |
| 4 | 3 | rspcev | |- ( ( suc A e. On /\ A e. suc A ) -> E. x e. On A e. x ) | 
| 5 | 1 2 4 | syl2anc | |- ( A e. On -> E. x e. On A e. x ) |