| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lspindpi.v | ⊢ 𝑉  =  ( Base ‘ 𝑊 ) | 
						
							| 2 |  | lspindpi.n | ⊢ 𝑁  =  ( LSpan ‘ 𝑊 ) | 
						
							| 3 |  | lspindpi.w | ⊢ ( 𝜑  →  𝑊  ∈  LVec ) | 
						
							| 4 |  | lspindpi.x | ⊢ ( 𝜑  →  𝑋  ∈  𝑉 ) | 
						
							| 5 |  | lspindpi.y | ⊢ ( 𝜑  →  𝑌  ∈  𝑉 ) | 
						
							| 6 |  | lspindpi.z | ⊢ ( 𝜑  →  𝑍  ∈  𝑉 ) | 
						
							| 7 |  | lspindpi.e | ⊢ ( 𝜑  →  ¬  𝑋  ∈  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) | 
						
							| 8 |  | lveclmod | ⊢ ( 𝑊  ∈  LVec  →  𝑊  ∈  LMod ) | 
						
							| 9 | 3 8 | syl | ⊢ ( 𝜑  →  𝑊  ∈  LMod ) | 
						
							| 10 |  | eqid | ⊢ ( LSubSp ‘ 𝑊 )  =  ( LSubSp ‘ 𝑊 ) | 
						
							| 11 | 10 | lsssssubg | ⊢ ( 𝑊  ∈  LMod  →  ( LSubSp ‘ 𝑊 )  ⊆  ( SubGrp ‘ 𝑊 ) ) | 
						
							| 12 | 9 11 | syl | ⊢ ( 𝜑  →  ( LSubSp ‘ 𝑊 )  ⊆  ( SubGrp ‘ 𝑊 ) ) | 
						
							| 13 | 1 10 2 | lspsncl | ⊢ ( ( 𝑊  ∈  LMod  ∧  𝑌  ∈  𝑉 )  →  ( 𝑁 ‘ { 𝑌 } )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 14 | 9 5 13 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 } )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 15 | 12 14 | sseldd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 } )  ∈  ( SubGrp ‘ 𝑊 ) ) | 
						
							| 16 | 1 10 2 | lspsncl | ⊢ ( ( 𝑊  ∈  LMod  ∧  𝑍  ∈  𝑉 )  →  ( 𝑁 ‘ { 𝑍 } )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 17 | 9 6 16 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑍 } )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 18 | 12 17 | sseldd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑍 } )  ∈  ( SubGrp ‘ 𝑊 ) ) | 
						
							| 19 |  | eqid | ⊢ ( LSSum ‘ 𝑊 )  =  ( LSSum ‘ 𝑊 ) | 
						
							| 20 | 19 | lsmub1 | ⊢ ( ( ( 𝑁 ‘ { 𝑌 } )  ∈  ( SubGrp ‘ 𝑊 )  ∧  ( 𝑁 ‘ { 𝑍 } )  ∈  ( SubGrp ‘ 𝑊 ) )  →  ( 𝑁 ‘ { 𝑌 } )  ⊆  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 21 | 15 18 20 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 } )  ⊆  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 22 | 1 2 19 9 5 6 | lsmpr | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 ,  𝑍 } )  =  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 23 | 21 22 | sseqtrrd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 } )  ⊆  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) | 
						
							| 24 |  | sseq1 | ⊢ ( ( 𝑁 ‘ { 𝑋 } )  =  ( 𝑁 ‘ { 𝑌 } )  →  ( ( 𝑁 ‘ { 𝑋 } )  ⊆  ( 𝑁 ‘ { 𝑌 ,  𝑍 } )  ↔  ( 𝑁 ‘ { 𝑌 } )  ⊆  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) ) | 
						
							| 25 | 23 24 | syl5ibrcom | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑋 } )  =  ( 𝑁 ‘ { 𝑌 } )  →  ( 𝑁 ‘ { 𝑋 } )  ⊆  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) ) | 
						
							| 26 | 1 10 2 9 5 6 | lspprcl | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 ,  𝑍 } )  ∈  ( LSubSp ‘ 𝑊 ) ) | 
						
							| 27 | 1 10 2 9 26 4 | ellspsn5b | ⊢ ( 𝜑  →  ( 𝑋  ∈  ( 𝑁 ‘ { 𝑌 ,  𝑍 } )  ↔  ( 𝑁 ‘ { 𝑋 } )  ⊆  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) ) | 
						
							| 28 | 25 27 | sylibrd | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑋 } )  =  ( 𝑁 ‘ { 𝑌 } )  →  𝑋  ∈  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) ) | 
						
							| 29 | 28 | necon3bd | ⊢ ( 𝜑  →  ( ¬  𝑋  ∈  ( 𝑁 ‘ { 𝑌 ,  𝑍 } )  →  ( 𝑁 ‘ { 𝑋 } )  ≠  ( 𝑁 ‘ { 𝑌 } ) ) ) | 
						
							| 30 | 7 29 | mpd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑋 } )  ≠  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 31 | 19 | lsmub2 | ⊢ ( ( ( 𝑁 ‘ { 𝑌 } )  ∈  ( SubGrp ‘ 𝑊 )  ∧  ( 𝑁 ‘ { 𝑍 } )  ∈  ( SubGrp ‘ 𝑊 ) )  →  ( 𝑁 ‘ { 𝑍 } )  ⊆  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 32 | 15 18 31 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑍 } )  ⊆  ( ( 𝑁 ‘ { 𝑌 } ) ( LSSum ‘ 𝑊 ) ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 33 | 32 22 | sseqtrrd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑍 } )  ⊆  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) | 
						
							| 34 |  | sseq1 | ⊢ ( ( 𝑁 ‘ { 𝑋 } )  =  ( 𝑁 ‘ { 𝑍 } )  →  ( ( 𝑁 ‘ { 𝑋 } )  ⊆  ( 𝑁 ‘ { 𝑌 ,  𝑍 } )  ↔  ( 𝑁 ‘ { 𝑍 } )  ⊆  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) ) | 
						
							| 35 | 33 34 | syl5ibrcom | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑋 } )  =  ( 𝑁 ‘ { 𝑍 } )  →  ( 𝑁 ‘ { 𝑋 } )  ⊆  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) ) | 
						
							| 36 | 35 27 | sylibrd | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑋 } )  =  ( 𝑁 ‘ { 𝑍 } )  →  𝑋  ∈  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) ) | 
						
							| 37 | 36 | necon3bd | ⊢ ( 𝜑  →  ( ¬  𝑋  ∈  ( 𝑁 ‘ { 𝑌 ,  𝑍 } )  →  ( 𝑁 ‘ { 𝑋 } )  ≠  ( 𝑁 ‘ { 𝑍 } ) ) ) | 
						
							| 38 | 7 37 | mpd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑋 } )  ≠  ( 𝑁 ‘ { 𝑍 } ) ) | 
						
							| 39 | 30 38 | jca | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑋 } )  ≠  ( 𝑁 ‘ { 𝑌 } )  ∧  ( 𝑁 ‘ { 𝑋 } )  ≠  ( 𝑁 ‘ { 𝑍 } ) ) ) |