| Step | Hyp | Ref | Expression | 
						
							| 1 |  | seqomlem.a |  |-  Q = rec ( ( i e. _om , v e. _V |-> <. suc i , ( i F v ) >. ) , <. (/) , ( _I ` I ) >. ) | 
						
							| 2 |  | frfnom |  |-  ( rec ( ( i e. _om , v e. _V |-> <. suc i , ( i F v ) >. ) , <. (/) , ( _I ` I ) >. ) |` _om ) Fn _om | 
						
							| 3 | 1 | reseq1i |  |-  ( Q |` _om ) = ( rec ( ( i e. _om , v e. _V |-> <. suc i , ( i F v ) >. ) , <. (/) , ( _I ` I ) >. ) |` _om ) | 
						
							| 4 | 3 | fneq1i |  |-  ( ( Q |` _om ) Fn _om <-> ( rec ( ( i e. _om , v e. _V |-> <. suc i , ( i F v ) >. ) , <. (/) , ( _I ` I ) >. ) |` _om ) Fn _om ) | 
						
							| 5 | 2 4 | mpbir |  |-  ( Q |` _om ) Fn _om | 
						
							| 6 |  | fvres |  |-  ( b e. _om -> ( ( Q |` _om ) ` b ) = ( Q ` b ) ) | 
						
							| 7 | 1 | seqomlem1 |  |-  ( b e. _om -> ( Q ` b ) = <. b , ( 2nd ` ( Q ` b ) ) >. ) | 
						
							| 8 | 6 7 | eqtrd |  |-  ( b e. _om -> ( ( Q |` _om ) ` b ) = <. b , ( 2nd ` ( Q ` b ) ) >. ) | 
						
							| 9 |  | fvex |  |-  ( 2nd ` ( Q ` b ) ) e. _V | 
						
							| 10 |  | opelxpi |  |-  ( ( b e. _om /\ ( 2nd ` ( Q ` b ) ) e. _V ) -> <. b , ( 2nd ` ( Q ` b ) ) >. e. ( _om X. _V ) ) | 
						
							| 11 | 9 10 | mpan2 |  |-  ( b e. _om -> <. b , ( 2nd ` ( Q ` b ) ) >. e. ( _om X. _V ) ) | 
						
							| 12 | 8 11 | eqeltrd |  |-  ( b e. _om -> ( ( Q |` _om ) ` b ) e. ( _om X. _V ) ) | 
						
							| 13 | 12 | rgen |  |-  A. b e. _om ( ( Q |` _om ) ` b ) e. ( _om X. _V ) | 
						
							| 14 |  | ffnfv |  |-  ( ( Q |` _om ) : _om --> ( _om X. _V ) <-> ( ( Q |` _om ) Fn _om /\ A. b e. _om ( ( Q |` _om ) ` b ) e. ( _om X. _V ) ) ) | 
						
							| 15 | 5 13 14 | mpbir2an |  |-  ( Q |` _om ) : _om --> ( _om X. _V ) | 
						
							| 16 |  | frn |  |-  ( ( Q |` _om ) : _om --> ( _om X. _V ) -> ran ( Q |` _om ) C_ ( _om X. _V ) ) | 
						
							| 17 | 15 16 | ax-mp |  |-  ran ( Q |` _om ) C_ ( _om X. _V ) | 
						
							| 18 |  | df-br |  |-  ( a ran ( Q |` _om ) b <-> <. a , b >. e. ran ( Q |` _om ) ) | 
						
							| 19 |  | fvelrnb |  |-  ( ( Q |` _om ) Fn _om -> ( <. a , b >. e. ran ( Q |` _om ) <-> E. c e. _om ( ( Q |` _om ) ` c ) = <. a , b >. ) ) | 
						
							| 20 | 5 19 | ax-mp |  |-  ( <. a , b >. e. ran ( Q |` _om ) <-> E. c e. _om ( ( Q |` _om ) ` c ) = <. a , b >. ) | 
						
							| 21 |  | fvres |  |-  ( c e. _om -> ( ( Q |` _om ) ` c ) = ( Q ` c ) ) | 
						
							| 22 | 21 | eqeq1d |  |-  ( c e. _om -> ( ( ( Q |` _om ) ` c ) = <. a , b >. <-> ( Q ` c ) = <. a , b >. ) ) | 
						
							| 23 | 22 | rexbiia |  |-  ( E. c e. _om ( ( Q |` _om ) ` c ) = <. a , b >. <-> E. c e. _om ( Q ` c ) = <. a , b >. ) | 
						
							| 24 | 18 20 23 | 3bitri |  |-  ( a ran ( Q |` _om ) b <-> E. c e. _om ( Q ` c ) = <. a , b >. ) | 
						
							| 25 | 1 | seqomlem1 |  |-  ( c e. _om -> ( Q ` c ) = <. c , ( 2nd ` ( Q ` c ) ) >. ) | 
						
							| 26 | 25 | adantl |  |-  ( ( a e. _om /\ c e. _om ) -> ( Q ` c ) = <. c , ( 2nd ` ( Q ` c ) ) >. ) | 
						
							| 27 | 26 | eqeq1d |  |-  ( ( a e. _om /\ c e. _om ) -> ( ( Q ` c ) = <. a , b >. <-> <. c , ( 2nd ` ( Q ` c ) ) >. = <. a , b >. ) ) | 
						
							| 28 |  | vex |  |-  c e. _V | 
						
							| 29 |  | fvex |  |-  ( 2nd ` ( Q ` c ) ) e. _V | 
						
							| 30 | 28 29 | opth1 |  |-  ( <. c , ( 2nd ` ( Q ` c ) ) >. = <. a , b >. -> c = a ) | 
						
							| 31 | 27 30 | biimtrdi |  |-  ( ( a e. _om /\ c e. _om ) -> ( ( Q ` c ) = <. a , b >. -> c = a ) ) | 
						
							| 32 |  | fveqeq2 |  |-  ( c = a -> ( ( Q ` c ) = <. a , b >. <-> ( Q ` a ) = <. a , b >. ) ) | 
						
							| 33 | 32 | biimpd |  |-  ( c = a -> ( ( Q ` c ) = <. a , b >. -> ( Q ` a ) = <. a , b >. ) ) | 
						
							| 34 | 31 33 | syli |  |-  ( ( a e. _om /\ c e. _om ) -> ( ( Q ` c ) = <. a , b >. -> ( Q ` a ) = <. a , b >. ) ) | 
						
							| 35 |  | fveq2 |  |-  ( ( Q ` a ) = <. a , b >. -> ( 2nd ` ( Q ` a ) ) = ( 2nd ` <. a , b >. ) ) | 
						
							| 36 |  | vex |  |-  a e. _V | 
						
							| 37 |  | vex |  |-  b e. _V | 
						
							| 38 | 36 37 | op2nd |  |-  ( 2nd ` <. a , b >. ) = b | 
						
							| 39 | 35 38 | eqtr2di |  |-  ( ( Q ` a ) = <. a , b >. -> b = ( 2nd ` ( Q ` a ) ) ) | 
						
							| 40 | 34 39 | syl6 |  |-  ( ( a e. _om /\ c e. _om ) -> ( ( Q ` c ) = <. a , b >. -> b = ( 2nd ` ( Q ` a ) ) ) ) | 
						
							| 41 | 40 | rexlimdva |  |-  ( a e. _om -> ( E. c e. _om ( Q ` c ) = <. a , b >. -> b = ( 2nd ` ( Q ` a ) ) ) ) | 
						
							| 42 | 1 | seqomlem1 |  |-  ( a e. _om -> ( Q ` a ) = <. a , ( 2nd ` ( Q ` a ) ) >. ) | 
						
							| 43 |  | fveqeq2 |  |-  ( c = a -> ( ( Q ` c ) = <. a , ( 2nd ` ( Q ` a ) ) >. <-> ( Q ` a ) = <. a , ( 2nd ` ( Q ` a ) ) >. ) ) | 
						
							| 44 | 43 | rspcev |  |-  ( ( a e. _om /\ ( Q ` a ) = <. a , ( 2nd ` ( Q ` a ) ) >. ) -> E. c e. _om ( Q ` c ) = <. a , ( 2nd ` ( Q ` a ) ) >. ) | 
						
							| 45 | 42 44 | mpdan |  |-  ( a e. _om -> E. c e. _om ( Q ` c ) = <. a , ( 2nd ` ( Q ` a ) ) >. ) | 
						
							| 46 |  | opeq2 |  |-  ( b = ( 2nd ` ( Q ` a ) ) -> <. a , b >. = <. a , ( 2nd ` ( Q ` a ) ) >. ) | 
						
							| 47 | 46 | eqeq2d |  |-  ( b = ( 2nd ` ( Q ` a ) ) -> ( ( Q ` c ) = <. a , b >. <-> ( Q ` c ) = <. a , ( 2nd ` ( Q ` a ) ) >. ) ) | 
						
							| 48 | 47 | rexbidv |  |-  ( b = ( 2nd ` ( Q ` a ) ) -> ( E. c e. _om ( Q ` c ) = <. a , b >. <-> E. c e. _om ( Q ` c ) = <. a , ( 2nd ` ( Q ` a ) ) >. ) ) | 
						
							| 49 | 45 48 | syl5ibrcom |  |-  ( a e. _om -> ( b = ( 2nd ` ( Q ` a ) ) -> E. c e. _om ( Q ` c ) = <. a , b >. ) ) | 
						
							| 50 | 41 49 | impbid |  |-  ( a e. _om -> ( E. c e. _om ( Q ` c ) = <. a , b >. <-> b = ( 2nd ` ( Q ` a ) ) ) ) | 
						
							| 51 | 24 50 | bitrid |  |-  ( a e. _om -> ( a ran ( Q |` _om ) b <-> b = ( 2nd ` ( Q ` a ) ) ) ) | 
						
							| 52 | 51 | alrimiv |  |-  ( a e. _om -> A. b ( a ran ( Q |` _om ) b <-> b = ( 2nd ` ( Q ` a ) ) ) ) | 
						
							| 53 |  | fvex |  |-  ( 2nd ` ( Q ` a ) ) e. _V | 
						
							| 54 |  | eqeq2 |  |-  ( c = ( 2nd ` ( Q ` a ) ) -> ( b = c <-> b = ( 2nd ` ( Q ` a ) ) ) ) | 
						
							| 55 | 54 | bibi2d |  |-  ( c = ( 2nd ` ( Q ` a ) ) -> ( ( a ran ( Q |` _om ) b <-> b = c ) <-> ( a ran ( Q |` _om ) b <-> b = ( 2nd ` ( Q ` a ) ) ) ) ) | 
						
							| 56 | 55 | albidv |  |-  ( c = ( 2nd ` ( Q ` a ) ) -> ( A. b ( a ran ( Q |` _om ) b <-> b = c ) <-> A. b ( a ran ( Q |` _om ) b <-> b = ( 2nd ` ( Q ` a ) ) ) ) ) | 
						
							| 57 | 53 56 | spcev |  |-  ( A. b ( a ran ( Q |` _om ) b <-> b = ( 2nd ` ( Q ` a ) ) ) -> E. c A. b ( a ran ( Q |` _om ) b <-> b = c ) ) | 
						
							| 58 | 52 57 | syl |  |-  ( a e. _om -> E. c A. b ( a ran ( Q |` _om ) b <-> b = c ) ) | 
						
							| 59 |  | eu6 |  |-  ( E! b a ran ( Q |` _om ) b <-> E. c A. b ( a ran ( Q |` _om ) b <-> b = c ) ) | 
						
							| 60 | 58 59 | sylibr |  |-  ( a e. _om -> E! b a ran ( Q |` _om ) b ) | 
						
							| 61 | 60 | rgen |  |-  A. a e. _om E! b a ran ( Q |` _om ) b | 
						
							| 62 |  | dff3 |  |-  ( ran ( Q |` _om ) : _om --> _V <-> ( ran ( Q |` _om ) C_ ( _om X. _V ) /\ A. a e. _om E! b a ran ( Q |` _om ) b ) ) | 
						
							| 63 | 17 61 62 | mpbir2an |  |-  ran ( Q |` _om ) : _om --> _V | 
						
							| 64 |  | df-ima |  |-  ( Q " _om ) = ran ( Q |` _om ) | 
						
							| 65 | 64 | feq1i |  |-  ( ( Q " _om ) : _om --> _V <-> ran ( Q |` _om ) : _om --> _V ) | 
						
							| 66 | 63 65 | mpbir |  |-  ( Q " _om ) : _om --> _V | 
						
							| 67 |  | dffn2 |  |-  ( ( Q " _om ) Fn _om <-> ( Q " _om ) : _om --> _V ) | 
						
							| 68 | 66 67 | mpbir |  |-  ( Q " _om ) Fn _om |