| Step | Hyp | Ref | Expression | 
						
							| 1 |  | f1osng |  | 
						
							| 2 | 1 | ad2antrr |  | 
						
							| 3 |  | f1osng |  | 
						
							| 4 | 3 | ad2antlr |  | 
						
							| 5 |  | disjsn2 |  | 
						
							| 6 | 5 | ad2antrl |  | 
						
							| 7 |  | disjsn2 |  | 
						
							| 8 | 7 | ad2antll |  | 
						
							| 9 |  | f1oun |  | 
						
							| 10 | 2 4 6 8 9 | syl22anc |  | 
						
							| 11 |  | df-pr |  | 
						
							| 12 | 11 | eqcomi |  | 
						
							| 13 | 12 | a1i |  | 
						
							| 14 |  | df-pr |  | 
						
							| 15 | 14 | eqcomi |  | 
						
							| 16 | 15 | a1i |  | 
						
							| 17 |  | df-pr |  | 
						
							| 18 | 17 | eqcomi |  | 
						
							| 19 | 18 | a1i |  | 
						
							| 20 | 13 16 19 | f1oeq123d |  | 
						
							| 21 | 10 20 | mpbid |  | 
						
							| 22 | 21 | ex |  |