| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lspindp1.v | ⊢ 𝑉  =  ( Base ‘ 𝑊 ) | 
						
							| 2 |  | lspindp1.o | ⊢  0   =  ( 0g ‘ 𝑊 ) | 
						
							| 3 |  | lspindp1.n | ⊢ 𝑁  =  ( LSpan ‘ 𝑊 ) | 
						
							| 4 |  | lspindp1.w | ⊢ ( 𝜑  →  𝑊  ∈  LVec ) | 
						
							| 5 |  | lspindp1.y | ⊢ ( 𝜑  →  𝑋  ∈  ( 𝑉  ∖  {  0  } ) ) | 
						
							| 6 |  | lspindp1.z | ⊢ ( 𝜑  →  𝑌  ∈  𝑉 ) | 
						
							| 7 |  | lspindp1.x | ⊢ ( 𝜑  →  𝑍  ∈  𝑉 ) | 
						
							| 8 |  | lspindp1.q | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑋 } )  ≠  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 9 |  | lspindp1.e | ⊢ ( 𝜑  →  ¬  𝑍  ∈  ( 𝑁 ‘ { 𝑋 ,  𝑌 } ) ) | 
						
							| 10 | 1 2 3 4 5 6 7 8 9 | lspindp1 | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑍 } )  ≠  ( 𝑁 ‘ { 𝑌 } )  ∧  ¬  𝑋  ∈  ( 𝑁 ‘ { 𝑍 ,  𝑌 } ) ) ) | 
						
							| 11 | 10 | simpld | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑍 } )  ≠  ( 𝑁 ‘ { 𝑌 } ) ) | 
						
							| 12 | 11 | necomd | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑌 } )  ≠  ( 𝑁 ‘ { 𝑍 } ) ) | 
						
							| 13 | 10 | simprd | ⊢ ( 𝜑  →  ¬  𝑋  ∈  ( 𝑁 ‘ { 𝑍 ,  𝑌 } ) ) | 
						
							| 14 |  | prcom | ⊢ { 𝑍 ,  𝑌 }  =  { 𝑌 ,  𝑍 } | 
						
							| 15 | 14 | fveq2i | ⊢ ( 𝑁 ‘ { 𝑍 ,  𝑌 } )  =  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) | 
						
							| 16 | 15 | eleq2i | ⊢ ( 𝑋  ∈  ( 𝑁 ‘ { 𝑍 ,  𝑌 } )  ↔  𝑋  ∈  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) | 
						
							| 17 | 13 16 | sylnib | ⊢ ( 𝜑  →  ¬  𝑋  ∈  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) | 
						
							| 18 | 12 17 | jca | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑌 } )  ≠  ( 𝑁 ‘ { 𝑍 } )  ∧  ¬  𝑋  ∈  ( 𝑁 ‘ { 𝑌 ,  𝑍 } ) ) ) |