| Step | Hyp | Ref | Expression | 
						
							| 1 |  | hhsst.1 | ⊢ 𝑈  =  〈 〈  +ℎ  ,   ·ℎ  〉 ,  normℎ 〉 | 
						
							| 2 |  | hhsst.2 | ⊢ 𝑊  =  〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 | 
						
							| 3 | 2 | hhssnvt | ⊢ ( 𝐻  ∈   Sℋ   →  𝑊  ∈  NrmCVec ) | 
						
							| 4 |  | resss | ⊢ (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  ⊆   +ℎ | 
						
							| 5 |  | resss | ⊢ (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) )  ⊆   ·ℎ | 
						
							| 6 |  | resss | ⊢ ( normℎ  ↾  𝐻 )  ⊆  normℎ | 
						
							| 7 | 4 5 6 | 3pm3.2i | ⊢ ( (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  ⊆   +ℎ   ∧  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) )  ⊆   ·ℎ   ∧  ( normℎ  ↾  𝐻 )  ⊆  normℎ ) | 
						
							| 8 | 3 7 | jctir | ⊢ ( 𝐻  ∈   Sℋ   →  ( 𝑊  ∈  NrmCVec  ∧  ( (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  ⊆   +ℎ   ∧  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) )  ⊆   ·ℎ   ∧  ( normℎ  ↾  𝐻 )  ⊆  normℎ ) ) ) | 
						
							| 9 | 1 | hhnv | ⊢ 𝑈  ∈  NrmCVec | 
						
							| 10 | 1 | hhva | ⊢  +ℎ   =  (  +𝑣  ‘ 𝑈 ) | 
						
							| 11 | 2 | hhssva | ⊢ (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  =  (  +𝑣  ‘ 𝑊 ) | 
						
							| 12 | 1 | hhsm | ⊢  ·ℎ   =  (  ·𝑠OLD  ‘ 𝑈 ) | 
						
							| 13 | 2 | hhsssm | ⊢ (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) )  =  (  ·𝑠OLD  ‘ 𝑊 ) | 
						
							| 14 | 1 | hhnm | ⊢ normℎ  =  ( normCV ‘ 𝑈 ) | 
						
							| 15 | 2 | hhssnm | ⊢ ( normℎ  ↾  𝐻 )  =  ( normCV ‘ 𝑊 ) | 
						
							| 16 |  | eqid | ⊢ ( SubSp ‘ 𝑈 )  =  ( SubSp ‘ 𝑈 ) | 
						
							| 17 | 10 11 12 13 14 15 16 | isssp | ⊢ ( 𝑈  ∈  NrmCVec  →  ( 𝑊  ∈  ( SubSp ‘ 𝑈 )  ↔  ( 𝑊  ∈  NrmCVec  ∧  ( (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  ⊆   +ℎ   ∧  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) )  ⊆   ·ℎ   ∧  ( normℎ  ↾  𝐻 )  ⊆  normℎ ) ) ) ) | 
						
							| 18 | 9 17 | ax-mp | ⊢ ( 𝑊  ∈  ( SubSp ‘ 𝑈 )  ↔  ( 𝑊  ∈  NrmCVec  ∧  ( (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  ⊆   +ℎ   ∧  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) )  ⊆   ·ℎ   ∧  ( normℎ  ↾  𝐻 )  ⊆  normℎ ) ) ) | 
						
							| 19 | 8 18 | sylibr | ⊢ ( 𝐻  ∈   Sℋ   →  𝑊  ∈  ( SubSp ‘ 𝑈 ) ) |