| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-rtrcl |  | 
						
							| 2 |  | relexp0g |  | 
						
							| 3 |  | nn0ex |  | 
						
							| 4 |  | 0nn0 |  | 
						
							| 5 |  | oveq1 |  | 
						
							| 6 | 5 | iuneq2d |  | 
						
							| 7 |  | oveq2 |  | 
						
							| 8 | 7 | cbviunv |  | 
						
							| 9 | 6 8 | eqtrdi |  | 
						
							| 10 | 9 | cbvmptv |  | 
						
							| 11 | 10 | ov2ssiunov2 |  | 
						
							| 12 | 3 4 11 | mp3an23 |  | 
						
							| 13 | 2 12 | eqsstrrd |  | 
						
							| 14 |  | relexp1g |  | 
						
							| 15 |  | 1nn0 |  | 
						
							| 16 | 10 | ov2ssiunov2 |  | 
						
							| 17 | 3 15 16 | mp3an23 |  | 
						
							| 18 | 14 17 | eqsstrrd |  | 
						
							| 19 |  | nn0uz |  | 
						
							| 20 | 10 | iunrelexpuztr |  | 
						
							| 21 | 19 4 20 | mp3an23 |  | 
						
							| 22 |  | fvex |  | 
						
							| 23 |  | sseq2 |  | 
						
							| 24 |  | sseq2 |  | 
						
							| 25 |  | id |  | 
						
							| 26 | 25 25 | coeq12d |  | 
						
							| 27 | 26 25 | sseq12d |  | 
						
							| 28 | 23 24 27 | 3anbi123d |  | 
						
							| 29 | 28 | a1i |  | 
						
							| 30 | 29 | alrimiv |  | 
						
							| 31 |  | elabgt |  | 
						
							| 32 | 22 30 31 | sylancr |  | 
						
							| 33 | 13 18 21 32 | mpbir3and |  | 
						
							| 34 |  | intss1 |  | 
						
							| 35 | 33 34 | syl |  | 
						
							| 36 |  | vex |  | 
						
							| 37 |  | sseq2 |  | 
						
							| 38 |  | sseq2 |  | 
						
							| 39 |  | id |  | 
						
							| 40 | 39 39 | coeq12d |  | 
						
							| 41 | 40 39 | sseq12d |  | 
						
							| 42 | 37 38 41 | 3anbi123d |  | 
						
							| 43 | 36 42 | elab |  | 
						
							| 44 |  | eqid |  | 
						
							| 45 | 10 | iunrelexpmin2 |  | 
						
							| 46 | 44 45 | mpan2 |  | 
						
							| 47 | 46 | 19.21bi |  | 
						
							| 48 | 43 47 | biimtrid |  | 
						
							| 49 | 48 | ralrimiv |  | 
						
							| 50 |  | ssint |  | 
						
							| 51 | 49 50 | sylibr |  | 
						
							| 52 | 35 51 | eqssd |  | 
						
							| 53 |  | oveq1 |  | 
						
							| 54 | 53 | iuneq2d |  | 
						
							| 55 |  | eqid |  | 
						
							| 56 |  | ovex |  | 
						
							| 57 | 3 56 | iunex |  | 
						
							| 58 | 54 55 57 | fvmpt |  | 
						
							| 59 | 52 58 | eqtrd |  | 
						
							| 60 | 59 | mpteq2ia |  | 
						
							| 61 | 1 60 | eqtri |  |