| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eupths.i |  | 
						
							| 2 |  | upgriseupth.v |  | 
						
							| 3 | 1 | iseupthf1o |  | 
						
							| 4 | 3 | a1i |  | 
						
							| 5 | 2 1 | upgriswlk |  | 
						
							| 6 | 5 | anbi1d |  | 
						
							| 7 |  | simpr |  | 
						
							| 8 |  | simpl2 |  | 
						
							| 9 |  | simpl3 |  | 
						
							| 10 | 7 8 9 | 3jca |  | 
						
							| 11 |  | f1of |  | 
						
							| 12 |  | iswrdi |  | 
						
							| 13 | 11 12 | syl |  | 
						
							| 14 | 13 | 3anim1i |  | 
						
							| 15 |  | simp1 |  | 
						
							| 16 | 14 15 | jca |  | 
						
							| 17 | 10 16 | impbii |  | 
						
							| 18 | 17 | a1i |  | 
						
							| 19 | 4 6 18 | 3bitrd |  |