Description: A set is equinumerous to its Cartesian product with a singleton on the left. (Contributed by Stefan O'Rear, 21-Nov-2014)
Ref | Expression | ||
---|---|---|---|
Assertion | xpsnen2g | |- ( ( A e. V /\ B e. W ) -> ( { A } X. B ) ~~ B ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | snex | |- { A } e. _V |
|
2 | xpcomeng | |- ( ( { A } e. _V /\ B e. W ) -> ( { A } X. B ) ~~ ( B X. { A } ) ) |
|
3 | 1 2 | mpan | |- ( B e. W -> ( { A } X. B ) ~~ ( B X. { A } ) ) |
4 | xpsneng | |- ( ( B e. W /\ A e. V ) -> ( B X. { A } ) ~~ B ) |
|
5 | 4 | ancoms | |- ( ( A e. V /\ B e. W ) -> ( B X. { A } ) ~~ B ) |
6 | entr | |- ( ( ( { A } X. B ) ~~ ( B X. { A } ) /\ ( B X. { A } ) ~~ B ) -> ( { A } X. B ) ~~ B ) |
|
7 | 3 5 6 | syl2an2 | |- ( ( A e. V /\ B e. W ) -> ( { A } X. B ) ~~ B ) |