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Description: A subring of a unital ring is a subring of a non-unital ring. (Contributed by AV, 30-Mar-2025)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | subrgsubrng | |- ( A e. ( SubRing ` R ) -> A e. ( SubRng ` R ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | eqid | |- ( Base ` R ) = ( Base ` R ) |
|
| 2 | eqid | |- ( 1r ` R ) = ( 1r ` R ) |
|
| 3 | 1 2 | issubrg | |- ( A e. ( SubRing ` R ) <-> ( ( R e. Ring /\ ( R |`s A ) e. Ring ) /\ ( A C_ ( Base ` R ) /\ ( 1r ` R ) e. A ) ) ) |
| 4 | ringrng | |- ( R e. Ring -> R e. Rng ) |
|
| 5 | 4 | ad2antrr | |- ( ( ( R e. Ring /\ ( R |`s A ) e. Ring ) /\ ( A C_ ( Base ` R ) /\ ( 1r ` R ) e. A ) ) -> R e. Rng ) |
| 6 | ringrng | |- ( ( R |`s A ) e. Ring -> ( R |`s A ) e. Rng ) |
|
| 7 | 6 | ad2antlr | |- ( ( ( R e. Ring /\ ( R |`s A ) e. Ring ) /\ ( A C_ ( Base ` R ) /\ ( 1r ` R ) e. A ) ) -> ( R |`s A ) e. Rng ) |
| 8 | simprl | |- ( ( ( R e. Ring /\ ( R |`s A ) e. Ring ) /\ ( A C_ ( Base ` R ) /\ ( 1r ` R ) e. A ) ) -> A C_ ( Base ` R ) ) |
|
| 9 | 1 | issubrng | |- ( A e. ( SubRng ` R ) <-> ( R e. Rng /\ ( R |`s A ) e. Rng /\ A C_ ( Base ` R ) ) ) |
| 10 | 5 7 8 9 | syl3anbrc | |- ( ( ( R e. Ring /\ ( R |`s A ) e. Ring ) /\ ( A C_ ( Base ` R ) /\ ( 1r ` R ) e. A ) ) -> A e. ( SubRng ` R ) ) |
| 11 | 3 10 | sylbi | |- ( A e. ( SubRing ` R ) -> A e. ( SubRng ` R ) ) |