| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ntrnei.o |  | 
						
							| 2 |  | ntrnei.f |  | 
						
							| 3 |  | ntrnei.r |  | 
						
							| 4 |  | df-ss |  | 
						
							| 5 | 4 | imbi2i |  | 
						
							| 6 |  | 19.21v |  | 
						
							| 7 | 5 6 | bitr4i |  | 
						
							| 8 |  | ax-1 |  | 
						
							| 9 |  | simpll |  | 
						
							| 10 | 1 2 3 | ntrneiiex |  | 
						
							| 11 |  | elmapi |  | 
						
							| 12 | 9 10 11 | 3syl |  | 
						
							| 13 |  | simplr |  | 
						
							| 14 | 12 13 | ffvelcdmd |  | 
						
							| 15 | 14 | elpwid |  | 
						
							| 16 | 15 | sselda |  | 
						
							| 17 | 16 | pm2.24d |  | 
						
							| 18 | 17 | ex |  | 
						
							| 19 | 18 | com23 |  | 
						
							| 20 | 19 | a1dd |  | 
						
							| 21 |  | idd |  | 
						
							| 22 | 20 21 | jad |  | 
						
							| 23 | 8 22 | impbid2 |  | 
						
							| 24 | 23 | albidv |  | 
						
							| 25 |  | df-ral |  | 
						
							| 26 | 24 25 | bitr4di |  | 
						
							| 27 | 3 | ad3antrrr |  | 
						
							| 28 |  | simpr |  | 
						
							| 29 |  | simpllr |  | 
						
							| 30 | 1 2 27 28 29 | ntrneiel |  | 
						
							| 31 |  | simplr |  | 
						
							| 32 | 1 2 27 28 31 | ntrneiel |  | 
						
							| 33 | 30 32 | imbi12d |  | 
						
							| 34 | 33 | imbi2d |  | 
						
							| 35 |  | impexp |  | 
						
							| 36 |  | ancomst |  | 
						
							| 37 | 35 36 | bitr3i |  | 
						
							| 38 | 34 37 | bitrdi |  | 
						
							| 39 | 38 | ralbidva |  | 
						
							| 40 | 26 39 | bitrd |  | 
						
							| 41 | 7 40 | bitrid |  | 
						
							| 42 | 41 | ralbidva |  | 
						
							| 43 |  | ralcom |  | 
						
							| 44 | 42 43 | bitrdi |  | 
						
							| 45 | 44 | ralbidva |  | 
						
							| 46 |  | ralcom |  | 
						
							| 47 | 45 46 | bitrdi |  |