| Step | Hyp | Ref | Expression | 
						
							| 1 |  | hhsst.1 | ⊢ 𝑈  =  〈 〈  +ℎ  ,   ·ℎ  〉 ,  normℎ 〉 | 
						
							| 2 |  | hhsst.2 | ⊢ 𝑊  =  〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 | 
						
							| 3 |  | hhssp3.3 | ⊢ 𝑊  ∈  ( SubSp ‘ 𝑈 ) | 
						
							| 4 |  | hhssp3.4 | ⊢ 𝐻  ⊆   ℋ | 
						
							| 5 |  | eqid | ⊢ ( BaseSet ‘ 𝑊 )  =  ( BaseSet ‘ 𝑊 ) | 
						
							| 6 |  | eqid | ⊢ (  +𝑣  ‘ 𝑊 )  =  (  +𝑣  ‘ 𝑊 ) | 
						
							| 7 | 5 6 | bafval | ⊢ ( BaseSet ‘ 𝑊 )  =  ran  (  +𝑣  ‘ 𝑊 ) | 
						
							| 8 | 1 | hhnv | ⊢ 𝑈  ∈  NrmCVec | 
						
							| 9 |  | eqid | ⊢ ( SubSp ‘ 𝑈 )  =  ( SubSp ‘ 𝑈 ) | 
						
							| 10 | 9 | sspnv | ⊢ ( ( 𝑈  ∈  NrmCVec  ∧  𝑊  ∈  ( SubSp ‘ 𝑈 ) )  →  𝑊  ∈  NrmCVec ) | 
						
							| 11 | 8 3 10 | mp2an | ⊢ 𝑊  ∈  NrmCVec | 
						
							| 12 | 6 | nvgrp | ⊢ ( 𝑊  ∈  NrmCVec  →  (  +𝑣  ‘ 𝑊 )  ∈  GrpOp ) | 
						
							| 13 |  | grporndm | ⊢ ( (  +𝑣  ‘ 𝑊 )  ∈  GrpOp  →  ran  (  +𝑣  ‘ 𝑊 )  =  dom  dom  (  +𝑣  ‘ 𝑊 ) ) | 
						
							| 14 | 11 12 13 | mp2b | ⊢ ran  (  +𝑣  ‘ 𝑊 )  =  dom  dom  (  +𝑣  ‘ 𝑊 ) | 
						
							| 15 | 2 | fveq2i | ⊢ (  +𝑣  ‘ 𝑊 )  =  (  +𝑣  ‘ 〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 ) | 
						
							| 16 |  | eqid | ⊢ (  +𝑣  ‘ 〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 )  =  (  +𝑣  ‘ 〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 ) | 
						
							| 17 | 16 | vafval | ⊢ (  +𝑣  ‘ 〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 )  =  ( 1st  ‘ ( 1st  ‘ 〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 ) ) | 
						
							| 18 |  | opex | ⊢ 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉  ∈  V | 
						
							| 19 |  | normf | ⊢ normℎ :  ℋ ⟶ ℝ | 
						
							| 20 |  | ax-hilex | ⊢  ℋ  ∈  V | 
						
							| 21 |  | fex | ⊢ ( ( normℎ :  ℋ ⟶ ℝ  ∧   ℋ  ∈  V )  →  normℎ  ∈  V ) | 
						
							| 22 | 19 20 21 | mp2an | ⊢ normℎ  ∈  V | 
						
							| 23 | 22 | resex | ⊢ ( normℎ  ↾  𝐻 )  ∈  V | 
						
							| 24 | 18 23 | op1st | ⊢ ( 1st  ‘ 〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 )  =  〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 | 
						
							| 25 | 24 | fveq2i | ⊢ ( 1st  ‘ ( 1st  ‘ 〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 ) )  =  ( 1st  ‘ 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ) | 
						
							| 26 |  | hilablo | ⊢  +ℎ   ∈  AbelOp | 
						
							| 27 |  | resexg | ⊢ (  +ℎ   ∈  AbelOp  →  (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  ∈  V ) | 
						
							| 28 | 26 27 | ax-mp | ⊢ (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  ∈  V | 
						
							| 29 |  | hvmulex | ⊢  ·ℎ   ∈  V | 
						
							| 30 | 29 | resex | ⊢ (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) )  ∈  V | 
						
							| 31 | 28 30 | op1st | ⊢ ( 1st  ‘ 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 )  =  (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) | 
						
							| 32 | 25 31 | eqtri | ⊢ ( 1st  ‘ ( 1st  ‘ 〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 ) )  =  (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) | 
						
							| 33 | 17 32 | eqtri | ⊢ (  +𝑣  ‘ 〈 〈 (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) ,  (  ·ℎ   ↾  ( ℂ  ×  𝐻 ) ) 〉 ,  ( normℎ  ↾  𝐻 ) 〉 )  =  (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) | 
						
							| 34 | 15 33 | eqtri | ⊢ (  +𝑣  ‘ 𝑊 )  =  (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) | 
						
							| 35 | 34 | dmeqi | ⊢ dom  (  +𝑣  ‘ 𝑊 )  =  dom  (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) ) | 
						
							| 36 |  | xpss12 | ⊢ ( ( 𝐻  ⊆   ℋ  ∧  𝐻  ⊆   ℋ )  →  ( 𝐻  ×  𝐻 )  ⊆  (  ℋ  ×   ℋ ) ) | 
						
							| 37 | 4 4 36 | mp2an | ⊢ ( 𝐻  ×  𝐻 )  ⊆  (  ℋ  ×   ℋ ) | 
						
							| 38 |  | ax-hfvadd | ⊢  +ℎ  : (  ℋ  ×   ℋ ) ⟶  ℋ | 
						
							| 39 | 38 | fdmi | ⊢ dom   +ℎ   =  (  ℋ  ×   ℋ ) | 
						
							| 40 | 37 39 | sseqtrri | ⊢ ( 𝐻  ×  𝐻 )  ⊆  dom   +ℎ | 
						
							| 41 |  | ssdmres | ⊢ ( ( 𝐻  ×  𝐻 )  ⊆  dom   +ℎ   ↔  dom  (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  =  ( 𝐻  ×  𝐻 ) ) | 
						
							| 42 | 40 41 | mpbi | ⊢ dom  (  +ℎ   ↾  ( 𝐻  ×  𝐻 ) )  =  ( 𝐻  ×  𝐻 ) | 
						
							| 43 | 35 42 | eqtri | ⊢ dom  (  +𝑣  ‘ 𝑊 )  =  ( 𝐻  ×  𝐻 ) | 
						
							| 44 | 43 | dmeqi | ⊢ dom  dom  (  +𝑣  ‘ 𝑊 )  =  dom  ( 𝐻  ×  𝐻 ) | 
						
							| 45 |  | dmxpid | ⊢ dom  ( 𝐻  ×  𝐻 )  =  𝐻 | 
						
							| 46 | 44 45 | eqtri | ⊢ dom  dom  (  +𝑣  ‘ 𝑊 )  =  𝐻 | 
						
							| 47 | 14 46 | eqtri | ⊢ ran  (  +𝑣  ‘ 𝑊 )  =  𝐻 | 
						
							| 48 | 7 47 | eqtri | ⊢ ( BaseSet ‘ 𝑊 )  =  𝐻 | 
						
							| 49 | 48 | eqcomi | ⊢ 𝐻  =  ( BaseSet ‘ 𝑊 ) |