Description: Any set weakly dominates the empty set. (Contributed by Stefan O'Rear, 11-Feb-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | 0wdom | |- ( X e. V -> (/) ~<_* X ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eqid | |- (/) = (/) |
|
2 | 1 | orci | |- ( (/) = (/) \/ E. z z : X -onto-> (/) ) |
3 | brwdom | |- ( X e. V -> ( (/) ~<_* X <-> ( (/) = (/) \/ E. z z : X -onto-> (/) ) ) ) |
|
4 | 2 3 | mpbiri | |- ( X e. V -> (/) ~<_* X ) |