| Step | Hyp | Ref | Expression | 
						
							| 1 |  | coiun |  | 
						
							| 2 |  | inss1 |  | 
						
							| 3 |  | fndm |  | 
						
							| 4 | 2 3 | sseqtrid |  | 
						
							| 5 |  | dfco2a |  | 
						
							| 6 | 4 5 | syl |  | 
						
							| 7 | 6 | coeq2d |  | 
						
							| 8 |  | inss1 |  | 
						
							| 9 |  | dmxpss |  | 
						
							| 10 | 8 9 | sstri |  | 
						
							| 11 |  | dfco2a |  | 
						
							| 12 | 10 11 | ax-mp |  | 
						
							| 13 |  | fvex |  | 
						
							| 14 |  | fparlem1 |  | 
						
							| 15 |  | sneq |  | 
						
							| 16 | 15 | xpeq1d |  | 
						
							| 17 | 14 16 | eqtrid |  | 
						
							| 18 | 15 | imaeq2d |  | 
						
							| 19 |  | df-ima |  | 
						
							| 20 |  | ssid |  | 
						
							| 21 |  | xpssres |  | 
						
							| 22 | 20 21 | ax-mp |  | 
						
							| 23 | 22 | rneqi |  | 
						
							| 24 | 13 | snnz |  | 
						
							| 25 |  | rnxp |  | 
						
							| 26 | 24 25 | ax-mp |  | 
						
							| 27 | 23 26 | eqtri |  | 
						
							| 28 | 19 27 | eqtri |  | 
						
							| 29 | 18 28 | eqtrdi |  | 
						
							| 30 | 17 29 | xpeq12d |  | 
						
							| 31 | 13 30 | iunxsn |  | 
						
							| 32 | 12 31 | eqtri |  | 
						
							| 33 | 32 | cnveqi |  | 
						
							| 34 |  | cnvco |  | 
						
							| 35 |  | cnvxp |  | 
						
							| 36 | 33 34 35 | 3eqtr3i |  | 
						
							| 37 |  | fparlem1 |  | 
						
							| 38 | 37 | xpeq2i |  | 
						
							| 39 |  | fnsnfv |  | 
						
							| 40 | 39 | xpeq1d |  | 
						
							| 41 | 38 40 | eqtr3id |  | 
						
							| 42 | 41 | cnveqd |  | 
						
							| 43 |  | cnvxp |  | 
						
							| 44 | 42 43 | eqtrdi |  | 
						
							| 45 | 44 | coeq2d |  | 
						
							| 46 | 36 45 | eqtr3id |  | 
						
							| 47 | 46 | iuneq2dv |  | 
						
							| 48 | 1 7 47 | 3eqtr4a |  |