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Description: The projective subspace closure of the empty subspace. (Contributed by NM, 13-Sep-2013) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | pcl0b.a | |- A = ( Atoms ` K ) |
|
| pcl0b.c | |- U = ( PCl ` K ) |
||
| Assertion | pcl0bN | |- ( ( K e. HL /\ P C_ A ) -> ( ( U ` P ) = (/) <-> P = (/) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pcl0b.a | |- A = ( Atoms ` K ) |
|
| 2 | pcl0b.c | |- U = ( PCl ` K ) |
|
| 3 | 1 2 | pclssidN | |- ( ( K e. HL /\ P C_ A ) -> P C_ ( U ` P ) ) |
| 4 | eqimss | |- ( ( U ` P ) = (/) -> ( U ` P ) C_ (/) ) |
|
| 5 | 3 4 | sylan9ss | |- ( ( ( K e. HL /\ P C_ A ) /\ ( U ` P ) = (/) ) -> P C_ (/) ) |
| 6 | ss0 | |- ( P C_ (/) -> P = (/) ) |
|
| 7 | 5 6 | syl | |- ( ( ( K e. HL /\ P C_ A ) /\ ( U ` P ) = (/) ) -> P = (/) ) |
| 8 | fveq2 | |- ( P = (/) -> ( U ` P ) = ( U ` (/) ) ) |
|
| 9 | 2 | pcl0N | |- ( K e. HL -> ( U ` (/) ) = (/) ) |
| 10 | 8 9 | sylan9eqr | |- ( ( K e. HL /\ P = (/) ) -> ( U ` P ) = (/) ) |
| 11 | 10 | adantlr | |- ( ( ( K e. HL /\ P C_ A ) /\ P = (/) ) -> ( U ` P ) = (/) ) |
| 12 | 7 11 | impbida | |- ( ( K e. HL /\ P C_ A ) -> ( ( U ` P ) = (/) <-> P = (/) ) ) |