Description: Every non-unital ring is a subring of itself. (Contributed by AV, 14-Feb-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | subrngss.1 | ||
| Assertion | subrngid | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | subrngss.1 | ||
| 2 | id | ||
| 3 | 1 | ressid | |
| 4 | 3 2 | eqeltrd | |
| 5 | ssidd | ||
| 6 | 1 | issubrng | |
| 7 | 2 4 5 6 | syl3anbrc |