| Step | Hyp | Ref | Expression | 
						
							| 1 |  | israg.p | ⊢ 𝑃  =  ( Base ‘ 𝐺 ) | 
						
							| 2 |  | israg.d | ⊢  −   =  ( dist ‘ 𝐺 ) | 
						
							| 3 |  | israg.i | ⊢ 𝐼  =  ( Itv ‘ 𝐺 ) | 
						
							| 4 |  | israg.l | ⊢ 𝐿  =  ( LineG ‘ 𝐺 ) | 
						
							| 5 |  | israg.s | ⊢ 𝑆  =  ( pInvG ‘ 𝐺 ) | 
						
							| 6 |  | israg.g | ⊢ ( 𝜑  →  𝐺  ∈  TarskiG ) | 
						
							| 7 |  | israg.a | ⊢ ( 𝜑  →  𝐴  ∈  𝑃 ) | 
						
							| 8 |  | israg.b | ⊢ ( 𝜑  →  𝐵  ∈  𝑃 ) | 
						
							| 9 |  | israg.c | ⊢ ( 𝜑  →  𝐶  ∈  𝑃 ) | 
						
							| 10 |  | ragncol.1 | ⊢ ( 𝜑  →  〈“ 𝐴 𝐵 𝐶 ”〉  ∈  ( ∟G ‘ 𝐺 ) ) | 
						
							| 11 |  | ragncol.2 | ⊢ ( 𝜑  →  𝐴  ≠  𝐵 ) | 
						
							| 12 |  | ragncol.3 | ⊢ ( 𝜑  →  𝐶  ≠  𝐵 ) | 
						
							| 13 | 11 | neneqd | ⊢ ( 𝜑  →  ¬  𝐴  =  𝐵 ) | 
						
							| 14 | 12 | neneqd | ⊢ ( 𝜑  →  ¬  𝐶  =  𝐵 ) | 
						
							| 15 |  | ioran | ⊢ ( ¬  ( 𝐴  =  𝐵  ∨  𝐶  =  𝐵 )  ↔  ( ¬  𝐴  =  𝐵  ∧  ¬  𝐶  =  𝐵 ) ) | 
						
							| 16 | 13 14 15 | sylanbrc | ⊢ ( 𝜑  →  ¬  ( 𝐴  =  𝐵  ∨  𝐶  =  𝐵 ) ) | 
						
							| 17 | 6 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐶  ∈  ( 𝐴 𝐿 𝐵 )  ∨  𝐴  =  𝐵 ) )  →  𝐺  ∈  TarskiG ) | 
						
							| 18 | 7 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐶  ∈  ( 𝐴 𝐿 𝐵 )  ∨  𝐴  =  𝐵 ) )  →  𝐴  ∈  𝑃 ) | 
						
							| 19 | 8 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐶  ∈  ( 𝐴 𝐿 𝐵 )  ∨  𝐴  =  𝐵 ) )  →  𝐵  ∈  𝑃 ) | 
						
							| 20 | 9 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐶  ∈  ( 𝐴 𝐿 𝐵 )  ∨  𝐴  =  𝐵 ) )  →  𝐶  ∈  𝑃 ) | 
						
							| 21 | 10 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐶  ∈  ( 𝐴 𝐿 𝐵 )  ∨  𝐴  =  𝐵 ) )  →  〈“ 𝐴 𝐵 𝐶 ”〉  ∈  ( ∟G ‘ 𝐺 ) ) | 
						
							| 22 |  | simpr | ⊢ ( ( 𝜑  ∧  ( 𝐶  ∈  ( 𝐴 𝐿 𝐵 )  ∨  𝐴  =  𝐵 ) )  →  ( 𝐶  ∈  ( 𝐴 𝐿 𝐵 )  ∨  𝐴  =  𝐵 ) ) | 
						
							| 23 | 1 2 3 4 5 17 18 19 20 21 22 | ragflat3 | ⊢ ( ( 𝜑  ∧  ( 𝐶  ∈  ( 𝐴 𝐿 𝐵 )  ∨  𝐴  =  𝐵 ) )  →  ( 𝐴  =  𝐵  ∨  𝐶  =  𝐵 ) ) | 
						
							| 24 | 16 23 | mtand | ⊢ ( 𝜑  →  ¬  ( 𝐶  ∈  ( 𝐴 𝐿 𝐵 )  ∨  𝐴  =  𝐵 ) ) |