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Description: The projective subspace closure of the empty subspace. (Contributed by NM, 12-Sep-2013) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | pcl0.c | ⊢ 𝑈 = ( PCl ‘ 𝐾 ) | |
| Assertion | pcl0N | ⊢ ( 𝐾 ∈ HL → ( 𝑈 ‘ ∅ ) = ∅ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pcl0.c | ⊢ 𝑈 = ( PCl ‘ 𝐾 ) | |
| 2 | 0ss | ⊢ ∅ ⊆ ( Atoms ‘ 𝐾 ) | |
| 3 | eqid | ⊢ ( Atoms ‘ 𝐾 ) = ( Atoms ‘ 𝐾 ) | |
| 4 | eqid | ⊢ ( ⊥𝑃 ‘ 𝐾 ) = ( ⊥𝑃 ‘ 𝐾 ) | |
| 5 | 3 4 1 | pclss2polN | ⊢ ( ( 𝐾 ∈ HL ∧ ∅ ⊆ ( Atoms ‘ 𝐾 ) ) → ( 𝑈 ‘ ∅ ) ⊆ ( ( ⊥𝑃 ‘ 𝐾 ) ‘ ( ( ⊥𝑃 ‘ 𝐾 ) ‘ ∅ ) ) ) |
| 6 | 2 5 | mpan2 | ⊢ ( 𝐾 ∈ HL → ( 𝑈 ‘ ∅ ) ⊆ ( ( ⊥𝑃 ‘ 𝐾 ) ‘ ( ( ⊥𝑃 ‘ 𝐾 ) ‘ ∅ ) ) ) |
| 7 | 4 | 2pol0N | ⊢ ( 𝐾 ∈ HL → ( ( ⊥𝑃 ‘ 𝐾 ) ‘ ( ( ⊥𝑃 ‘ 𝐾 ) ‘ ∅ ) ) = ∅ ) |
| 8 | 6 7 | sseqtrd | ⊢ ( 𝐾 ∈ HL → ( 𝑈 ‘ ∅ ) ⊆ ∅ ) |
| 9 | ss0 | ⊢ ( ( 𝑈 ‘ ∅ ) ⊆ ∅ → ( 𝑈 ‘ ∅ ) = ∅ ) | |
| 10 | 8 9 | syl | ⊢ ( 𝐾 ∈ HL → ( 𝑈 ‘ ∅ ) = ∅ ) |