| Step | Hyp | Ref | Expression | 
						
							| 1 |  | h1de2.1 | ⊢ 𝐴  ∈   ℋ | 
						
							| 2 |  | h1de2.2 | ⊢ 𝐵  ∈   ℋ | 
						
							| 3 | 2 2 | hicli | ⊢ ( 𝐵  ·ih  𝐵 )  ∈  ℂ | 
						
							| 4 | 3 1 | hvmulcli | ⊢ ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ∈   ℋ | 
						
							| 5 | 1 2 | hicli | ⊢ ( 𝐴  ·ih  𝐵 )  ∈  ℂ | 
						
							| 6 | 5 2 | hvmulcli | ⊢ ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ∈   ℋ | 
						
							| 7 |  | his2sub | ⊢ ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ∈   ℋ  ∧  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ∈   ℋ  ∧  𝐴  ∈   ℋ )  →  ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐴 )  =  ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐴 )  −  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐴 ) ) ) | 
						
							| 8 | 4 6 1 7 | mp3an | ⊢ ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐴 )  =  ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐴 )  −  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐴 ) ) | 
						
							| 9 |  | ax-his3 | ⊢ ( ( ( 𝐵  ·ih  𝐵 )  ∈  ℂ  ∧  𝐴  ∈   ℋ  ∧  𝐴  ∈   ℋ )  →  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐴 )  =  ( ( 𝐵  ·ih  𝐵 )  ·  ( 𝐴  ·ih  𝐴 ) ) ) | 
						
							| 10 | 3 1 1 9 | mp3an | ⊢ ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐴 )  =  ( ( 𝐵  ·ih  𝐵 )  ·  ( 𝐴  ·ih  𝐴 ) ) | 
						
							| 11 | 1 1 | hicli | ⊢ ( 𝐴  ·ih  𝐴 )  ∈  ℂ | 
						
							| 12 | 3 11 | mulcomi | ⊢ ( ( 𝐵  ·ih  𝐵 )  ·  ( 𝐴  ·ih  𝐴 ) )  =  ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) ) | 
						
							| 13 | 10 12 | eqtri | ⊢ ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐴 )  =  ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) ) | 
						
							| 14 |  | ax-his3 | ⊢ ( ( ( 𝐴  ·ih  𝐵 )  ∈  ℂ  ∧  𝐵  ∈   ℋ  ∧  𝐴  ∈   ℋ )  →  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐴 )  =  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) ) ) | 
						
							| 15 | 5 2 1 14 | mp3an | ⊢ ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐴 )  =  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) ) | 
						
							| 16 | 13 15 | oveq12i | ⊢ ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐴 )  −  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐴 ) )  =  ( ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) )  −  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) ) ) | 
						
							| 17 | 8 16 | eqtr2i | ⊢ ( ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) )  −  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) ) )  =  ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐴 ) | 
						
							| 18 |  | his2sub | ⊢ ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ∈   ℋ  ∧  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ∈   ℋ  ∧  𝐵  ∈   ℋ )  →  ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐵 )  =  ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐵 )  −  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐵 ) ) ) | 
						
							| 19 | 4 6 2 18 | mp3an | ⊢ ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐵 )  =  ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐵 )  −  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐵 ) ) | 
						
							| 20 | 3 5 | mulcomi | ⊢ ( ( 𝐵  ·ih  𝐵 )  ·  ( 𝐴  ·ih  𝐵 ) )  =  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐵 ) ) | 
						
							| 21 |  | ax-his3 | ⊢ ( ( ( 𝐵  ·ih  𝐵 )  ∈  ℂ  ∧  𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ )  →  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐵 )  =  ( ( 𝐵  ·ih  𝐵 )  ·  ( 𝐴  ·ih  𝐵 ) ) ) | 
						
							| 22 | 3 1 2 21 | mp3an | ⊢ ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐵 )  =  ( ( 𝐵  ·ih  𝐵 )  ·  ( 𝐴  ·ih  𝐵 ) ) | 
						
							| 23 |  | ax-his3 | ⊢ ( ( ( 𝐴  ·ih  𝐵 )  ∈  ℂ  ∧  𝐵  ∈   ℋ  ∧  𝐵  ∈   ℋ )  →  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐵 )  =  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐵 ) ) ) | 
						
							| 24 | 5 2 2 23 | mp3an | ⊢ ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐵 )  =  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐵 ) ) | 
						
							| 25 | 20 22 24 | 3eqtr4i | ⊢ ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐵 )  =  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐵 ) | 
						
							| 26 | 4 2 | hicli | ⊢ ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐵 )  ∈  ℂ | 
						
							| 27 | 6 2 | hicli | ⊢ ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐵 )  ∈  ℂ | 
						
							| 28 | 26 27 | subeq0i | ⊢ ( ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐵 )  −  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐵 ) )  =  0  ↔  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐵 )  =  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐵 ) ) | 
						
							| 29 | 25 28 | mpbir | ⊢ ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  ·ih  𝐵 )  −  ( ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 )  ·ih  𝐵 ) )  =  0 | 
						
							| 30 | 19 29 | eqtri | ⊢ ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐵 )  =  0 | 
						
							| 31 | 2 | h1dei | ⊢ ( 𝐴  ∈  ( ⊥ ‘ ( ⊥ ‘ { 𝐵 } ) )  ↔  ( 𝐴  ∈   ℋ  ∧  ∀ 𝑥  ∈   ℋ ( ( 𝐵  ·ih  𝑥 )  =  0  →  ( 𝐴  ·ih  𝑥 )  =  0 ) ) ) | 
						
							| 32 | 1 31 | mpbiran | ⊢ ( 𝐴  ∈  ( ⊥ ‘ ( ⊥ ‘ { 𝐵 } ) )  ↔  ∀ 𝑥  ∈   ℋ ( ( 𝐵  ·ih  𝑥 )  =  0  →  ( 𝐴  ·ih  𝑥 )  =  0 ) ) | 
						
							| 33 | 4 6 | hvsubcli | ⊢ ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ∈   ℋ | 
						
							| 34 |  | oveq2 | ⊢ ( 𝑥  =  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  →  ( 𝐵  ·ih  𝑥 )  =  ( 𝐵  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) ) ) | 
						
							| 35 | 34 | eqeq1d | ⊢ ( 𝑥  =  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  →  ( ( 𝐵  ·ih  𝑥 )  =  0  ↔  ( 𝐵  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) ) | 
						
							| 36 |  | oveq2 | ⊢ ( 𝑥  =  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  →  ( 𝐴  ·ih  𝑥 )  =  ( 𝐴  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) ) ) | 
						
							| 37 | 36 | eqeq1d | ⊢ ( 𝑥  =  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  →  ( ( 𝐴  ·ih  𝑥 )  =  0  ↔  ( 𝐴  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) ) | 
						
							| 38 | 35 37 | imbi12d | ⊢ ( 𝑥  =  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  →  ( ( ( 𝐵  ·ih  𝑥 )  =  0  →  ( 𝐴  ·ih  𝑥 )  =  0 )  ↔  ( ( 𝐵  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0  →  ( 𝐴  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) ) ) | 
						
							| 39 | 38 | rspcv | ⊢ ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ∈   ℋ  →  ( ∀ 𝑥  ∈   ℋ ( ( 𝐵  ·ih  𝑥 )  =  0  →  ( 𝐴  ·ih  𝑥 )  =  0 )  →  ( ( 𝐵  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0  →  ( 𝐴  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) ) ) | 
						
							| 40 | 33 39 | ax-mp | ⊢ ( ∀ 𝑥  ∈   ℋ ( ( 𝐵  ·ih  𝑥 )  =  0  →  ( 𝐴  ·ih  𝑥 )  =  0 )  →  ( ( 𝐵  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0  →  ( 𝐴  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) ) | 
						
							| 41 | 32 40 | sylbi | ⊢ ( 𝐴  ∈  ( ⊥ ‘ ( ⊥ ‘ { 𝐵 } ) )  →  ( ( 𝐵  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0  →  ( 𝐴  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) ) | 
						
							| 42 |  | orthcom | ⊢ ( ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ∈   ℋ  ∧  𝐵  ∈   ℋ )  →  ( ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐵 )  =  0  ↔  ( 𝐵  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) ) | 
						
							| 43 | 33 2 42 | mp2an | ⊢ ( ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐵 )  =  0  ↔  ( 𝐵  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) | 
						
							| 44 |  | orthcom | ⊢ ( ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ∈   ℋ  ∧  𝐴  ∈   ℋ )  →  ( ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐴 )  =  0  ↔  ( 𝐴  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) ) | 
						
							| 45 | 33 1 44 | mp2an | ⊢ ( ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐴 )  =  0  ↔  ( 𝐴  ·ih  ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) )  =  0 ) | 
						
							| 46 | 41 43 45 | 3imtr4g | ⊢ ( 𝐴  ∈  ( ⊥ ‘ ( ⊥ ‘ { 𝐵 } ) )  →  ( ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐵 )  =  0  →  ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐴 )  =  0 ) ) | 
						
							| 47 | 30 46 | mpi | ⊢ ( 𝐴  ∈  ( ⊥ ‘ ( ⊥ ‘ { 𝐵 } ) )  →  ( ( ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  −ℎ  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) )  ·ih  𝐴 )  =  0 ) | 
						
							| 48 | 17 47 | eqtrid | ⊢ ( 𝐴  ∈  ( ⊥ ‘ ( ⊥ ‘ { 𝐵 } ) )  →  ( ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) )  −  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) ) )  =  0 ) | 
						
							| 49 | 11 3 | mulcli | ⊢ ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) )  ∈  ℂ | 
						
							| 50 | 2 1 | hicli | ⊢ ( 𝐵  ·ih  𝐴 )  ∈  ℂ | 
						
							| 51 | 5 50 | mulcli | ⊢ ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) )  ∈  ℂ | 
						
							| 52 | 49 51 | subeq0i | ⊢ ( ( ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) )  −  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) ) )  =  0  ↔  ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) )  =  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) ) ) | 
						
							| 53 | 48 52 | sylib | ⊢ ( 𝐴  ∈  ( ⊥ ‘ ( ⊥ ‘ { 𝐵 } ) )  →  ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) )  =  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) ) ) | 
						
							| 54 | 53 | eqcomd | ⊢ ( 𝐴  ∈  ( ⊥ ‘ ( ⊥ ‘ { 𝐵 } ) )  →  ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) )  =  ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) ) ) | 
						
							| 55 | 1 2 | bcseqi | ⊢ ( ( ( 𝐴  ·ih  𝐵 )  ·  ( 𝐵  ·ih  𝐴 ) )  =  ( ( 𝐴  ·ih  𝐴 )  ·  ( 𝐵  ·ih  𝐵 ) )  ↔  ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  =  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) | 
						
							| 56 | 54 55 | sylib | ⊢ ( 𝐴  ∈  ( ⊥ ‘ ( ⊥ ‘ { 𝐵 } ) )  →  ( ( 𝐵  ·ih  𝐵 )  ·ℎ  𝐴 )  =  ( ( 𝐴  ·ih  𝐵 )  ·ℎ  𝐵 ) ) |