| Step | Hyp | Ref | Expression | 
						
							| 0 |  | cA | ⊢ 𝐴 | 
						
							| 1 |  | chba | ⊢  ℋ | 
						
							| 2 | 0 1 | wcel | ⊢ 𝐴  ∈   ℋ | 
						
							| 3 |  | cB | ⊢ 𝐵 | 
						
							| 4 | 3 1 | wcel | ⊢ 𝐵  ∈   ℋ | 
						
							| 5 |  | cC | ⊢ 𝐶 | 
						
							| 6 | 5 1 | wcel | ⊢ 𝐶  ∈   ℋ | 
						
							| 7 | 2 4 6 | w3a | ⊢ ( 𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ ) | 
						
							| 8 |  | cva | ⊢  +ℎ | 
						
							| 9 | 0 3 8 | co | ⊢ ( 𝐴  +ℎ  𝐵 ) | 
						
							| 10 |  | csp | ⊢  ·ih | 
						
							| 11 | 9 5 10 | co | ⊢ ( ( 𝐴  +ℎ  𝐵 )  ·ih  𝐶 ) | 
						
							| 12 | 0 5 10 | co | ⊢ ( 𝐴  ·ih  𝐶 ) | 
						
							| 13 |  | caddc | ⊢  + | 
						
							| 14 | 3 5 10 | co | ⊢ ( 𝐵  ·ih  𝐶 ) | 
						
							| 15 | 12 14 13 | co | ⊢ ( ( 𝐴  ·ih  𝐶 )  +  ( 𝐵  ·ih  𝐶 ) ) | 
						
							| 16 | 11 15 | wceq | ⊢ ( ( 𝐴  +ℎ  𝐵 )  ·ih  𝐶 )  =  ( ( 𝐴  ·ih  𝐶 )  +  ( 𝐵  ·ih  𝐶 ) ) | 
						
							| 17 | 7 16 | wi | ⊢ ( ( 𝐴  ∈   ℋ  ∧  𝐵  ∈   ℋ  ∧  𝐶  ∈   ℋ )  →  ( ( 𝐴  +ℎ  𝐵 )  ·ih  𝐶 )  =  ( ( 𝐴  ·ih  𝐶 )  +  ( 𝐵  ·ih  𝐶 ) ) ) |