| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ax-his2 | ⊢ ( ( 𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ  ∧  𝐴  ∈   ℋ )  →  ( ( 𝐵  +ℎ  𝐶 )  ·ih  𝐴 )  =  ( ( 𝐵  ·ih  𝐴 )  +  ( 𝐶  ·ih  𝐴 ) ) ) | 
						
							| 2 | 1 | 3comr | ⊢ ( ( 𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ )  →  ( ( 𝐵  +ℎ  𝐶 )  ·ih  𝐴 )  =  ( ( 𝐵  ·ih  𝐴 )  +  ( 𝐶  ·ih  𝐴 ) ) ) | 
						
							| 3 |  | hvaddcl | ⊢ ( ( 𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ )  →  ( 𝐵  +ℎ  𝐶 )  ∈   ℋ ) | 
						
							| 4 |  | braval | ⊢ ( ( 𝐴  ∈   ℋ  ∧  ( 𝐵  +ℎ  𝐶 )  ∈   ℋ )  →  ( ( bra ‘ 𝐴 ) ‘ ( 𝐵  +ℎ  𝐶 ) )  =  ( ( 𝐵  +ℎ  𝐶 )  ·ih  𝐴 ) ) | 
						
							| 5 | 3 4 | sylan2 | ⊢ ( ( 𝐴  ∈   ℋ  ∧  ( 𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ ) )  →  ( ( bra ‘ 𝐴 ) ‘ ( 𝐵  +ℎ  𝐶 ) )  =  ( ( 𝐵  +ℎ  𝐶 )  ·ih  𝐴 ) ) | 
						
							| 6 | 5 | 3impb | ⊢ ( ( 𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ )  →  ( ( bra ‘ 𝐴 ) ‘ ( 𝐵  +ℎ  𝐶 ) )  =  ( ( 𝐵  +ℎ  𝐶 )  ·ih  𝐴 ) ) | 
						
							| 7 |  | braval | ⊢ ( ( 𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ )  →  ( ( bra ‘ 𝐴 ) ‘ 𝐵 )  =  ( 𝐵  ·ih  𝐴 ) ) | 
						
							| 8 | 7 | 3adant3 | ⊢ ( ( 𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ )  →  ( ( bra ‘ 𝐴 ) ‘ 𝐵 )  =  ( 𝐵  ·ih  𝐴 ) ) | 
						
							| 9 |  | braval | ⊢ ( ( 𝐴  ∈   ℋ  ∧  𝐶  ∈   ℋ )  →  ( ( bra ‘ 𝐴 ) ‘ 𝐶 )  =  ( 𝐶  ·ih  𝐴 ) ) | 
						
							| 10 | 9 | 3adant2 | ⊢ ( ( 𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ )  →  ( ( bra ‘ 𝐴 ) ‘ 𝐶 )  =  ( 𝐶  ·ih  𝐴 ) ) | 
						
							| 11 | 8 10 | oveq12d | ⊢ ( ( 𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ )  →  ( ( ( bra ‘ 𝐴 ) ‘ 𝐵 )  +  ( ( bra ‘ 𝐴 ) ‘ 𝐶 ) )  =  ( ( 𝐵  ·ih  𝐴 )  +  ( 𝐶  ·ih  𝐴 ) ) ) | 
						
							| 12 | 2 6 11 | 3eqtr4d | ⊢ ( ( 𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ )  →  ( ( bra ‘ 𝐴 ) ‘ ( 𝐵  +ℎ  𝐶 ) )  =  ( ( ( bra ‘ 𝐴 ) ‘ 𝐵 )  +  ( ( bra ‘ 𝐴 ) ‘ 𝐶 ) ) ) |