| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mirval.p | ⊢ 𝑃  =  ( Base ‘ 𝐺 ) | 
						
							| 2 |  | mirval.d | ⊢  −   =  ( dist ‘ 𝐺 ) | 
						
							| 3 |  | mirval.i | ⊢ 𝐼  =  ( Itv ‘ 𝐺 ) | 
						
							| 4 |  | mirval.l | ⊢ 𝐿  =  ( LineG ‘ 𝐺 ) | 
						
							| 5 |  | mirval.s | ⊢ 𝑆  =  ( pInvG ‘ 𝐺 ) | 
						
							| 6 |  | mirval.g | ⊢ ( 𝜑  →  𝐺  ∈  TarskiG ) | 
						
							| 7 |  | mirtrcgr.e | ⊢  ∼   =  ( cgrG ‘ 𝐺 ) | 
						
							| 8 |  | mirtrcgr.m | ⊢ 𝑀  =  ( 𝑆 ‘ 𝐵 ) | 
						
							| 9 |  | mirtrcgr.n | ⊢ 𝑁  =  ( 𝑆 ‘ 𝑌 ) | 
						
							| 10 |  | mirtrcgr.a | ⊢ ( 𝜑  →  𝐴  ∈  𝑃 ) | 
						
							| 11 |  | mirtrcgr.b | ⊢ ( 𝜑  →  𝐵  ∈  𝑃 ) | 
						
							| 12 |  | mirtrcgr.x | ⊢ ( 𝜑  →  𝑋  ∈  𝑃 ) | 
						
							| 13 |  | mirtrcgr.y | ⊢ ( 𝜑  →  𝑌  ∈  𝑃 ) | 
						
							| 14 |  | mircgrextend.1 | ⊢ ( 𝜑  →  ( 𝐴  −  𝐵 )  =  ( 𝑋  −  𝑌 ) ) | 
						
							| 15 | 1 2 3 4 5 6 11 8 10 | mircl | ⊢ ( 𝜑  →  ( 𝑀 ‘ 𝐴 )  ∈  𝑃 ) | 
						
							| 16 | 1 2 3 4 5 6 13 9 12 | mircl | ⊢ ( 𝜑  →  ( 𝑁 ‘ 𝑋 )  ∈  𝑃 ) | 
						
							| 17 | 1 2 3 4 5 6 11 8 10 | mirbtwn | ⊢ ( 𝜑  →  𝐵  ∈  ( ( 𝑀 ‘ 𝐴 ) 𝐼 𝐴 ) ) | 
						
							| 18 | 1 2 3 6 15 11 10 17 | tgbtwncom | ⊢ ( 𝜑  →  𝐵  ∈  ( 𝐴 𝐼 ( 𝑀 ‘ 𝐴 ) ) ) | 
						
							| 19 | 1 2 3 4 5 6 13 9 12 | mirbtwn | ⊢ ( 𝜑  →  𝑌  ∈  ( ( 𝑁 ‘ 𝑋 ) 𝐼 𝑋 ) ) | 
						
							| 20 | 1 2 3 6 16 13 12 19 | tgbtwncom | ⊢ ( 𝜑  →  𝑌  ∈  ( 𝑋 𝐼 ( 𝑁 ‘ 𝑋 ) ) ) | 
						
							| 21 | 1 2 3 6 10 11 12 13 14 | tgcgrcomlr | ⊢ ( 𝜑  →  ( 𝐵  −  𝐴 )  =  ( 𝑌  −  𝑋 ) ) | 
						
							| 22 | 1 2 3 4 5 6 11 8 10 | mircgr | ⊢ ( 𝜑  →  ( 𝐵  −  ( 𝑀 ‘ 𝐴 ) )  =  ( 𝐵  −  𝐴 ) ) | 
						
							| 23 | 1 2 3 4 5 6 13 9 12 | mircgr | ⊢ ( 𝜑  →  ( 𝑌  −  ( 𝑁 ‘ 𝑋 ) )  =  ( 𝑌  −  𝑋 ) ) | 
						
							| 24 | 21 22 23 | 3eqtr4d | ⊢ ( 𝜑  →  ( 𝐵  −  ( 𝑀 ‘ 𝐴 ) )  =  ( 𝑌  −  ( 𝑁 ‘ 𝑋 ) ) ) | 
						
							| 25 | 1 2 3 6 10 11 15 12 13 16 18 20 14 24 | tgcgrextend | ⊢ ( 𝜑  →  ( 𝐴  −  ( 𝑀 ‘ 𝐴 ) )  =  ( 𝑋  −  ( 𝑁 ‘ 𝑋 ) ) ) |