Description: A structure product of rings has closed binary operation. (Contributed by Mario Carneiro, 11-Mar-2015) (Proof shortened by AV, 30-Mar-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | prdsmulrcl.y | |- Y = ( S Xs_ R ) | |
| prdsmulrcl.b | |- B = ( Base ` Y ) | ||
| prdsmulrcl.t | |- .x. = ( .r ` Y ) | ||
| prdsmulrcl.s | |- ( ph -> S e. V ) | ||
| prdsmulrcl.i | |- ( ph -> I e. W ) | ||
| prdsmulrcl.r | |- ( ph -> R : I --> Ring ) | ||
| prdsmulrcl.f | |- ( ph -> F e. B ) | ||
| prdsmulrcl.g | |- ( ph -> G e. B ) | ||
| Assertion | prdsmulrcl | |- ( ph -> ( F .x. G ) e. B ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | prdsmulrcl.y | |- Y = ( S Xs_ R ) | |
| 2 | prdsmulrcl.b | |- B = ( Base ` Y ) | |
| 3 | prdsmulrcl.t | |- .x. = ( .r ` Y ) | |
| 4 | prdsmulrcl.s | |- ( ph -> S e. V ) | |
| 5 | prdsmulrcl.i | |- ( ph -> I e. W ) | |
| 6 | prdsmulrcl.r | |- ( ph -> R : I --> Ring ) | |
| 7 | prdsmulrcl.f | |- ( ph -> F e. B ) | |
| 8 | prdsmulrcl.g | |- ( ph -> G e. B ) | |
| 9 | ringssrng | |- Ring C_ Rng | |
| 10 | fss | |- ( ( R : I --> Ring /\ Ring C_ Rng ) -> R : I --> Rng ) | |
| 11 | 6 9 10 | sylancl | |- ( ph -> R : I --> Rng ) | 
| 12 | 1 2 3 4 5 11 7 8 | prdsmulrngcl | |- ( ph -> ( F .x. G ) e. B ) |