| Step | Hyp | Ref | Expression | 
						
							| 1 |  | sbcal |  | 
						
							| 2 |  | sbcal |  | 
						
							| 3 |  | sbcim2g |  | 
						
							| 4 |  | sbcg |  | 
						
							| 5 |  | sbcel2gv |  | 
						
							| 6 |  | sbcel2gv |  | 
						
							| 7 |  | imbi13 |  | 
						
							| 8 | 4 5 6 7 | syl3c |  | 
						
							| 9 | 3 8 | bitrd |  | 
						
							| 10 |  | pm3.31 |  | 
						
							| 11 |  | pm3.3 |  | 
						
							| 12 | 10 11 | impbii |  | 
						
							| 13 | 12 | sbcbii |  | 
						
							| 14 |  | pm3.31 |  | 
						
							| 15 |  | pm3.3 |  | 
						
							| 16 | 14 15 | impbii |  | 
						
							| 17 | 9 13 16 | 3bitr3g |  | 
						
							| 18 | 17 | albidv |  | 
						
							| 19 | 2 18 | bitrid |  | 
						
							| 20 | 19 | albidv |  | 
						
							| 21 | 1 20 | bitrid |  | 
						
							| 22 |  | dftr2 |  | 
						
							| 23 | 22 | sbcbii |  | 
						
							| 24 |  | dftr2 |  | 
						
							| 25 | 21 23 24 | 3bitr4g |  |