Description: The set of polynomial matrices over a commutative ring is an associative algebra. (Contributed by AV, 16-Jun-2024)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | pmatring.p | ||
| pmatring.c | |||
| Assertion | pmatassa | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | pmatring.p | ||
| 2 | pmatring.c | ||
| 3 | 1 | ply1crng | |
| 4 | 2 | matassa | |
| 5 | 3 4 | sylan2 |