Description: The intersection of two sets in a sigma-algebra is in the sigma-algebra. (Contributed by Glauco Siliprandi, 26-Jun-2021)
Ref | Expression | ||
---|---|---|---|
Hypotheses | salincld.1 | |- ( ph -> S e. SAlg ) |
|
salincld.2 | |- ( ph -> E e. S ) |
||
salincld.3 | |- ( ph -> F e. S ) |
||
Assertion | salincld | |- ( ph -> ( E i^i F ) e. S ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | salincld.1 | |- ( ph -> S e. SAlg ) |
|
2 | salincld.2 | |- ( ph -> E e. S ) |
|
3 | salincld.3 | |- ( ph -> F e. S ) |
|
4 | salincl | |- ( ( S e. SAlg /\ E e. S /\ F e. S ) -> ( E i^i F ) e. S ) |
|
5 | 1 2 3 4 | syl3anc | |- ( ph -> ( E i^i F ) e. S ) |