| Step | Hyp | Ref | Expression | 
						
							| 1 |  | uncfval.g |  | 
						
							| 2 |  | uncfval.c |  | 
						
							| 3 |  | uncfval.d |  | 
						
							| 4 |  | uncfval.f |  | 
						
							| 5 |  | uncf1.a |  | 
						
							| 6 |  | uncf1.b |  | 
						
							| 7 |  | uncf1.x |  | 
						
							| 8 |  | uncf1.y |  | 
						
							| 9 | 1 2 3 4 | uncfval |  | 
						
							| 10 | 9 | fveq2d |  | 
						
							| 11 | 10 | oveqd |  | 
						
							| 12 |  | df-ov |  | 
						
							| 13 |  | eqid |  | 
						
							| 14 | 13 5 6 | xpcbas |  | 
						
							| 15 |  | eqid |  | 
						
							| 16 |  | eqid |  | 
						
							| 17 |  | funcrcl |  | 
						
							| 18 | 4 17 | syl |  | 
						
							| 19 | 18 | simpld |  | 
						
							| 20 |  | eqid |  | 
						
							| 21 | 13 19 2 20 | 1stfcl |  | 
						
							| 22 | 21 4 | cofucl |  | 
						
							| 23 |  | eqid |  | 
						
							| 24 | 13 19 2 23 | 2ndfcl |  | 
						
							| 25 | 15 16 22 24 | prfcl |  | 
						
							| 26 |  | eqid |  | 
						
							| 27 |  | eqid |  | 
						
							| 28 | 26 27 2 3 | evlfcl |  | 
						
							| 29 | 7 8 | opelxpd |  | 
						
							| 30 | 14 25 28 29 | cofu1 |  | 
						
							| 31 | 12 30 | eqtrid |  | 
						
							| 32 |  | eqid |  | 
						
							| 33 | 15 14 32 22 24 29 | prf1 |  | 
						
							| 34 | 14 21 4 29 | cofu1 |  | 
						
							| 35 | 13 14 32 19 2 20 29 | 1stf1 |  | 
						
							| 36 |  | op1stg |  | 
						
							| 37 | 7 8 36 | syl2anc |  | 
						
							| 38 | 35 37 | eqtrd |  | 
						
							| 39 | 38 | fveq2d |  | 
						
							| 40 | 34 39 | eqtrd |  | 
						
							| 41 | 13 14 32 19 2 23 29 | 2ndf1 |  | 
						
							| 42 |  | op2ndg |  | 
						
							| 43 | 7 8 42 | syl2anc |  | 
						
							| 44 | 41 43 | eqtrd |  | 
						
							| 45 | 40 44 | opeq12d |  | 
						
							| 46 | 33 45 | eqtrd |  | 
						
							| 47 | 46 | fveq2d |  | 
						
							| 48 |  | df-ov |  | 
						
							| 49 | 47 48 | eqtr4di |  | 
						
							| 50 | 27 | fucbas |  | 
						
							| 51 |  | relfunc |  | 
						
							| 52 |  | 1st2ndbr |  | 
						
							| 53 | 51 4 52 | sylancr |  | 
						
							| 54 | 5 50 53 | funcf1 |  | 
						
							| 55 | 54 7 | ffvelcdmd |  | 
						
							| 56 | 26 2 3 6 55 8 | evlf1 |  | 
						
							| 57 | 49 56 | eqtrd |  | 
						
							| 58 | 11 31 57 | 3eqtrd |  |