Description: In a commutative ring, the product of two ideals is a subset of their intersection. (Contributed by Thierry Arnoux, 17-Jun-2024)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | idlsrgmulrssin.1 | |- S = ( IDLsrg ` R ) | |
| idlsrgmulrssin.2 | |- B = ( LIdeal ` R ) | ||
| idlsrgmulrssin.3 | |- .(x) = ( .r ` S ) | ||
| idlsrgmulrssin.4 | |- ( ph -> R e. CRing ) | ||
| idlsrgmulrssin.5 | |- ( ph -> I e. B ) | ||
| idlsrgmulrssin.6 | |- ( ph -> J e. B ) | ||
| Assertion | idlsrgmulrssin | |- ( ph -> ( I .(x) J ) C_ ( I i^i J ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | idlsrgmulrssin.1 | |- S = ( IDLsrg ` R ) | |
| 2 | idlsrgmulrssin.2 | |- B = ( LIdeal ` R ) | |
| 3 | idlsrgmulrssin.3 | |- .(x) = ( .r ` S ) | |
| 4 | idlsrgmulrssin.4 | |- ( ph -> R e. CRing ) | |
| 5 | idlsrgmulrssin.5 | |- ( ph -> I e. B ) | |
| 6 | idlsrgmulrssin.6 | |- ( ph -> J e. B ) | |
| 7 | eqid | |- ( .r ` R ) = ( .r ` R ) | |
| 8 | 1 2 3 7 4 5 6 | idlsrgmulrss1 | |- ( ph -> ( I .(x) J ) C_ I ) | 
| 9 | 4 | crngringd | |- ( ph -> R e. Ring ) | 
| 10 | 1 2 3 7 9 5 6 | idlsrgmulrss2 | |- ( ph -> ( I .(x) J ) C_ J ) | 
| 11 | 8 10 | ssind | |- ( ph -> ( I .(x) J ) C_ ( I i^i J ) ) |