| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mapdpglem.h | ⊢ 𝐻  =  ( LHyp ‘ 𝐾 ) | 
						
							| 2 |  | mapdpglem.m | ⊢ 𝑀  =  ( ( mapd ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 3 |  | mapdpglem.u | ⊢ 𝑈  =  ( ( DVecH ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 4 |  | mapdpglem.v | ⊢ 𝑉  =  ( Base ‘ 𝑈 ) | 
						
							| 5 |  | mapdpglem.s | ⊢  −   =  ( -g ‘ 𝑈 ) | 
						
							| 6 |  | mapdpglem.n | ⊢ 𝑁  =  ( LSpan ‘ 𝑈 ) | 
						
							| 7 |  | mapdpglem.c | ⊢ 𝐶  =  ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 8 |  | mapdpglem.k | ⊢ ( 𝜑  →  ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 ) ) | 
						
							| 9 |  | mapdpglem.x | ⊢ ( 𝜑  →  𝑋  ∈  𝑉 ) | 
						
							| 10 |  | mapdpglem.y | ⊢ ( 𝜑  →  𝑌  ∈  𝑉 ) | 
						
							| 11 |  | mapdpglem1.p | ⊢  ⊕   =  ( LSSum ‘ 𝐶 ) | 
						
							| 12 |  | mapdpglem2.j | ⊢ 𝐽  =  ( LSpan ‘ 𝐶 ) | 
						
							| 13 |  | mapdpglem3.f | ⊢ 𝐹  =  ( Base ‘ 𝐶 ) | 
						
							| 14 |  | mapdpglem3.te | ⊢ ( 𝜑  →  𝑡  ∈  ( ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  ⊕  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑌 } ) ) ) ) | 
						
							| 15 | 1 7 8 | lcdlmod | ⊢ ( 𝜑  →  𝐶  ∈  LMod ) | 
						
							| 16 |  | eqid | ⊢ ( LSubSp ‘ 𝑈 )  =  ( LSubSp ‘ 𝑈 ) | 
						
							| 17 |  | eqid | ⊢ ( LSubSp ‘ 𝐶 )  =  ( LSubSp ‘ 𝐶 ) | 
						
							| 18 | 1 3 8 | dvhlmod | ⊢ ( 𝜑  →  𝑈  ∈  LMod ) | 
						
							| 19 | 4 16 6 | lspsncl | ⊢ ( ( 𝑈  ∈  LMod  ∧  𝑋  ∈  𝑉 )  →  ( 𝑁 ‘ { 𝑋 } )  ∈  ( LSubSp ‘ 𝑈 ) ) | 
						
							| 20 | 18 9 19 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑋 } )  ∈  ( LSubSp ‘ 𝑈 ) ) | 
						
							| 21 | 1 2 3 16 7 17 8 20 | mapdcl2 | ⊢ ( 𝜑  →  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  ∈  ( LSubSp ‘ 𝐶 ) ) | 
						
							| 22 | 4 16 6 | lspsncl | ⊢ ( ( 𝑈  ∈  LMod  ∧  𝑌  ∈  𝑉 )  →  ( 𝑁 ‘ { 𝑌 } )  ∈  ( LSubSp ‘ 𝑈 ) ) | 
						
							| 23 | 18 10 22 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 } )  ∈  ( LSubSp ‘ 𝑈 ) ) | 
						
							| 24 | 1 2 3 16 7 17 8 23 | mapdcl2 | ⊢ ( 𝜑  →  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑌 } ) )  ∈  ( LSubSp ‘ 𝐶 ) ) | 
						
							| 25 | 17 11 | lsmcl | ⊢ ( ( 𝐶  ∈  LMod  ∧  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  ∈  ( LSubSp ‘ 𝐶 )  ∧  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑌 } ) )  ∈  ( LSubSp ‘ 𝐶 ) )  →  ( ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  ⊕  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑌 } ) ) )  ∈  ( LSubSp ‘ 𝐶 ) ) | 
						
							| 26 | 15 21 24 25 | syl3anc | ⊢ ( 𝜑  →  ( ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  ⊕  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑌 } ) ) )  ∈  ( LSubSp ‘ 𝐶 ) ) | 
						
							| 27 | 13 17 | lssel | ⊢ ( ( ( ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  ⊕  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑌 } ) ) )  ∈  ( LSubSp ‘ 𝐶 )  ∧  𝑡  ∈  ( ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  ⊕  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑌 } ) ) ) )  →  𝑡  ∈  𝐹 ) | 
						
							| 28 | 26 14 27 | syl2anc | ⊢ ( 𝜑  →  𝑡  ∈  𝐹 ) |