Description: The ring module over a commutative ring is an associative algebra. (Contributed by Mario Carneiro, 6-Oct-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | rlmassa |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | crngring | ||
| 2 | eqid | ||
| 3 | 2 | subrgid | |
| 4 | 1 3 | syl | |
| 5 | rlmval | ||
| 6 | 5 | sraassa | |
| 7 | 4 6 | mpdan |