| Step | Hyp | Ref | Expression | 
						
							| 1 |  | hdmaplna2.h | ⊢ 𝐻  =  ( LHyp ‘ 𝐾 ) | 
						
							| 2 |  | hdmaplna2.u | ⊢ 𝑈  =  ( ( DVecH ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 3 |  | hdmaplna2.v | ⊢ 𝑉  =  ( Base ‘ 𝑈 ) | 
						
							| 4 |  | hdmaplna2.p | ⊢  +   =  ( +g ‘ 𝑈 ) | 
						
							| 5 |  | hdmaplna2.r | ⊢ 𝑅  =  ( Scalar ‘ 𝑈 ) | 
						
							| 6 |  | hdmaplna2.q | ⊢  ⨣   =  ( +g ‘ 𝑅 ) | 
						
							| 7 |  | hdmaplna2.s | ⊢ 𝑆  =  ( ( HDMap ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 8 |  | hdmaplna2.k | ⊢ ( 𝜑  →  ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 ) ) | 
						
							| 9 |  | hdmaplna2.x | ⊢ ( 𝜑  →  𝑋  ∈  𝑉 ) | 
						
							| 10 |  | hdmaplna2.y | ⊢ ( 𝜑  →  𝑌  ∈  𝑉 ) | 
						
							| 11 |  | hdmaplna2.z | ⊢ ( 𝜑  →  𝑍  ∈  𝑉 ) | 
						
							| 12 |  | eqid | ⊢ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 )  =  ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 13 |  | eqid | ⊢ ( +g ‘ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) )  =  ( +g ‘ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) ) | 
						
							| 14 | 1 2 3 4 12 13 7 8 10 11 | hdmapadd | ⊢ ( 𝜑  →  ( 𝑆 ‘ ( 𝑌  +  𝑍 ) )  =  ( ( 𝑆 ‘ 𝑌 ) ( +g ‘ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) ) ( 𝑆 ‘ 𝑍 ) ) ) | 
						
							| 15 | 14 | fveq1d | ⊢ ( 𝜑  →  ( ( 𝑆 ‘ ( 𝑌  +  𝑍 ) ) ‘ 𝑋 )  =  ( ( ( 𝑆 ‘ 𝑌 ) ( +g ‘ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) ) ( 𝑆 ‘ 𝑍 ) ) ‘ 𝑋 ) ) | 
						
							| 16 |  | eqid | ⊢ ( Base ‘ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) )  =  ( Base ‘ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) ) | 
						
							| 17 | 1 2 3 12 16 7 8 10 | hdmapcl | ⊢ ( 𝜑  →  ( 𝑆 ‘ 𝑌 )  ∈  ( Base ‘ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) ) ) | 
						
							| 18 | 1 2 3 12 16 7 8 11 | hdmapcl | ⊢ ( 𝜑  →  ( 𝑆 ‘ 𝑍 )  ∈  ( Base ‘ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) ) ) | 
						
							| 19 | 1 2 3 5 6 12 16 13 8 17 18 9 | lcdvaddval | ⊢ ( 𝜑  →  ( ( ( 𝑆 ‘ 𝑌 ) ( +g ‘ ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) ) ( 𝑆 ‘ 𝑍 ) ) ‘ 𝑋 )  =  ( ( ( 𝑆 ‘ 𝑌 ) ‘ 𝑋 )  ⨣  ( ( 𝑆 ‘ 𝑍 ) ‘ 𝑋 ) ) ) | 
						
							| 20 | 15 19 | eqtrd | ⊢ ( 𝜑  →  ( ( 𝑆 ‘ ( 𝑌  +  𝑍 ) ) ‘ 𝑋 )  =  ( ( ( 𝑆 ‘ 𝑌 ) ‘ 𝑋 )  ⨣  ( ( 𝑆 ‘ 𝑍 ) ‘ 𝑋 ) ) ) |