| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ausgr.1 |  | 
						
							| 2 |  | ausgrusgri.1 |  | 
						
							| 3 |  | fvex |  | 
						
							| 4 |  | fvex |  | 
						
							| 5 | 1 | isausgr |  | 
						
							| 6 | 3 4 5 | mp2an |  | 
						
							| 7 |  | edgval |  | 
						
							| 8 | 7 | a1i |  | 
						
							| 9 | 8 | sseq1d |  | 
						
							| 10 | 2 | eleq2i |  | 
						
							| 11 |  | fvex |  | 
						
							| 12 |  | id |  | 
						
							| 13 |  | dmeq |  | 
						
							| 14 |  | rneq |  | 
						
							| 15 | 12 13 14 | f1eq123d |  | 
						
							| 16 | 11 15 | elab |  | 
						
							| 17 | 10 16 | sylbb |  | 
						
							| 18 | 17 | 3ad2ant3 |  | 
						
							| 19 |  | simp2 |  | 
						
							| 20 |  | f1ssr |  | 
						
							| 21 | 18 19 20 | syl2anc |  | 
						
							| 22 | 21 | 3exp |  | 
						
							| 23 | 9 22 | sylbid |  | 
						
							| 24 | 6 23 | biimtrid |  | 
						
							| 25 | 24 | 3imp |  | 
						
							| 26 |  | eqid |  | 
						
							| 27 |  | eqid |  | 
						
							| 28 | 26 27 | isusgrs |  | 
						
							| 29 | 28 | 3ad2ant1 |  | 
						
							| 30 | 25 29 | mpbird |  |