| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mapdindp1.v | ⊢ 𝑉  =  ( Base ‘ 𝑊 ) | 
						
							| 2 |  | mapdindp1.p | ⊢  +   =  ( +g ‘ 𝑊 ) | 
						
							| 3 |  | mapdindp1.o | ⊢  0   =  ( 0g ‘ 𝑊 ) | 
						
							| 4 |  | mapdindp1.n | ⊢ 𝑁  =  ( LSpan ‘ 𝑊 ) | 
						
							| 5 |  | mapdindp1.w | ⊢ ( 𝜑  →  𝑊  ∈  LVec ) | 
						
							| 6 |  | mapdindp1.x | ⊢ ( 𝜑  →  𝑋  ∈  ( 𝑉  ∖  {  0  } ) ) | 
						
							| 7 |  | mapdindp1.y | ⊢ ( 𝜑  →  𝑌  ∈  ( 𝑉  ∖  {  0  } ) ) | 
						
							| 8 |  | mapdindp1.z | ⊢ ( 𝜑  →  𝑍  ∈  ( 𝑉  ∖  {  0  } ) ) | 
						
							| 9 |  | mapdindp1.W | ⊢ ( 𝜑  →  𝑤  ∈  ( 𝑉  ∖  {  0  } ) ) | 
						
							| 10 |  | mapdindp1.e | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 } )  =  ( 𝑁 ‘ { 𝑍 } ) ) | 
						
							| 11 |  | mapdindp1.ne | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑋 } )  ≠  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 12 |  | mapdindp1.f | ⊢ ( 𝜑  →  ¬  𝑤  ∈  ( 𝑁 ‘ { 𝑋 ,  𝑌 } ) ) | 
						
							| 13 |  | mapdindp1.yz | ⊢ ( 𝜑  →  ( 𝑌  +  𝑍 )  ≠   0  ) | 
						
							| 14 |  | eqid | ⊢ ( LSubSp ‘ 𝑊 )  =  ( LSubSp ‘ 𝑊 ) | 
						
							| 15 |  | lveclmod | ⊢ ( 𝑊  ∈  LVec  →  𝑊  ∈  LMod ) | 
						
							| 16 | 5 15 | syl | ⊢ ( 𝜑  →  𝑊  ∈  LMod ) | 
						
							| 17 | 7 | eldifad | ⊢ ( 𝜑  →  𝑌  ∈  𝑉 ) | 
						
							| 18 | 1 14 4 | lspsncl | ⊢ ( ( 𝑊  ∈  LMod  ∧  𝑌  ∈  𝑉 )  →  ( 𝑁 ‘ { 𝑌 } )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 19 | 16 17 18 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 } )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 20 | 10 19 | eqeltrrd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑍 } )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 21 |  | eqid | ⊢ ( LSSum ‘ 𝑊 )  =  ( LSSum ‘ 𝑊 ) | 
						
							| 22 | 14 21 | lsmcl | ⊢ ( ( 𝑊  ∈  LMod  ∧  ( 𝑁 ‘ { 𝑌 } )  ∈  ( LSubSp ‘ 𝑊 )  ∧  ( 𝑁 ‘ { 𝑍 } )  ∈  ( LSubSp ‘ 𝑊 ) )  →  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 23 | 16 19 20 22 | syl3anc | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 24 | 14 | lsssssubg | ⊢ ( 𝑊  ∈  LMod  →  ( LSubSp ‘ 𝑊 )  ⊆  ( SubGrp ‘ 𝑊 ) ) | 
						
							| 25 | 16 24 | syl | ⊢ ( 𝜑  →  ( LSubSp ‘ 𝑊 )  ⊆  ( SubGrp ‘ 𝑊 ) ) | 
						
							| 26 | 25 19 | sseldd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 } )  ∈  ( SubGrp ‘ 𝑊 ) ) | 
						
							| 27 | 10 26 | eqeltrrd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑍 } )  ∈  ( SubGrp ‘ 𝑊 ) ) | 
						
							| 28 | 1 4 | lspsnid | ⊢ ( ( 𝑊  ∈  LMod  ∧  𝑌  ∈  𝑉 )  →  𝑌  ∈  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 29 | 16 17 28 | syl2anc | ⊢ ( 𝜑  →  𝑌  ∈  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 30 | 8 | eldifad | ⊢ ( 𝜑  →  𝑍  ∈  𝑉 ) | 
						
							| 31 | 1 4 | lspsnid | ⊢ ( ( 𝑊  ∈  LMod  ∧  𝑍  ∈  𝑉 )  →  𝑍  ∈  ( 𝑁 ‘ { 𝑍 } ) ) | 
						
							| 32 | 16 30 31 | syl2anc | ⊢ ( 𝜑  →  𝑍  ∈  ( 𝑁 ‘ { 𝑍 } ) ) | 
						
							| 33 | 2 21 | lsmelvali | ⊢ ( ( ( ( 𝑁 ‘ { 𝑌 } )  ∈  ( SubGrp ‘ 𝑊 )  ∧  ( 𝑁 ‘ { 𝑍 } )  ∈  ( SubGrp ‘ 𝑊 ) )  ∧  ( 𝑌  ∈  ( 𝑁 ‘ { 𝑌 } )  ∧  𝑍  ∈  ( 𝑁 ‘ { 𝑍 } ) ) )  →  ( 𝑌  +  𝑍 )  ∈  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 34 | 26 27 29 32 33 | syl22anc | ⊢ ( 𝜑  →  ( 𝑌  +  𝑍 )  ∈  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 35 | 14 4 16 23 34 | ellspsn5 | ⊢ ( 𝜑  →  ( 𝑁 ‘ { ( 𝑌  +  𝑍 ) } )  ⊆  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 36 | 10 | oveq2d | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑌 } ) )  =  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 37 | 21 | lsmidm | ⊢ ( ( 𝑁 ‘ { 𝑌 } )  ∈  ( SubGrp ‘ 𝑊 )  →  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑌 } ) )  =  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 38 | 26 37 | syl | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑌 } ) )  =  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 39 | 36 38 | eqtr3d | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) )  =  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 40 | 35 39 | sseqtrd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { ( 𝑌  +  𝑍 ) } )  ⊆  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 41 | 1 2 | lmodvacl | ⊢ ( ( 𝑊  ∈  LMod  ∧  𝑌  ∈  𝑉  ∧  𝑍  ∈  𝑉 )  →  ( 𝑌  +  𝑍 )  ∈  𝑉 ) | 
						
							| 42 | 16 17 30 41 | syl3anc | ⊢ ( 𝜑  →  ( 𝑌  +  𝑍 )  ∈  𝑉 ) | 
						
							| 43 |  | eldifsn | ⊢ ( ( 𝑌  +  𝑍 )  ∈  ( 𝑉  ∖  {  0  } )  ↔  ( ( 𝑌  +  𝑍 )  ∈  𝑉  ∧  ( 𝑌  +  𝑍 )  ≠   0  ) ) | 
						
							| 44 | 42 13 43 | sylanbrc | ⊢ ( 𝜑  →  ( 𝑌  +  𝑍 )  ∈  ( 𝑉  ∖  {  0  } ) ) | 
						
							| 45 | 1 3 4 5 44 17 | lspsncmp | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { ( 𝑌  +  𝑍 ) } )  ⊆  ( 𝑁 ‘ { 𝑌 } )  ↔  ( 𝑁 ‘ { ( 𝑌  +  𝑍 ) } )  =  ( 𝑁 ‘ { 𝑌 } ) ) ) | 
						
							| 46 | 40 45 | mpbid | ⊢ ( 𝜑  →  ( 𝑁 ‘ { ( 𝑌  +  𝑍 ) } )  =  ( 𝑁 ‘ { 𝑌 } ) ) |