| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ipolub.i |  | 
						
							| 2 |  | ipolub.f |  | 
						
							| 3 |  | ipolub.s |  | 
						
							| 4 |  | ipolublem.l |  | 
						
							| 5 |  | unissb |  | 
						
							| 6 | 2 | ad2antrr |  | 
						
							| 7 | 3 | ad2antrr |  | 
						
							| 8 |  | simpr |  | 
						
							| 9 | 7 8 | sseldd |  | 
						
							| 10 |  | simplr |  | 
						
							| 11 | 1 4 | ipole |  | 
						
							| 12 | 6 9 10 11 | syl3anc |  | 
						
							| 13 | 12 | ralbidva |  | 
						
							| 14 | 5 13 | bitr4id |  | 
						
							| 15 |  | unissb |  | 
						
							| 16 | 6 | adantlr |  | 
						
							| 17 | 9 | adantlr |  | 
						
							| 18 |  | simplr |  | 
						
							| 19 | 1 4 | ipole |  | 
						
							| 20 | 16 17 18 19 | syl3anc |  | 
						
							| 21 | 20 | ralbidva |  | 
						
							| 22 | 15 21 | bitr4id |  | 
						
							| 23 | 2 | ad2antrr |  | 
						
							| 24 |  | simplr |  | 
						
							| 25 |  | simpr |  | 
						
							| 26 | 1 4 | ipole |  | 
						
							| 27 | 23 24 25 26 | syl3anc |  | 
						
							| 28 | 27 | bicomd |  | 
						
							| 29 | 22 28 | imbi12d |  | 
						
							| 30 | 29 | ralbidva |  | 
						
							| 31 | 14 30 | anbi12d |  |