| Step | Hyp | Ref | Expression | 
						
							| 1 |  | efgval.w |  |-  W = ( _I ` Word ( I X. 2o ) ) | 
						
							| 2 |  | efgval.r |  |-  .~ = ( ~FG ` I ) | 
						
							| 3 |  | efgval2.m |  |-  M = ( y e. I , z e. 2o |-> <. y , ( 1o \ z ) >. ) | 
						
							| 4 |  | efgval2.t |  |-  T = ( v e. W |-> ( n e. ( 0 ... ( # ` v ) ) , w e. ( I X. 2o ) |-> ( v splice <. n , n , <" w ( M ` w ) "> >. ) ) ) | 
						
							| 5 | 1 2 | efgval |  |-  .~ = |^| { r | ( r Er W /\ A. x e. W A. m e. ( 0 ... ( # ` x ) ) A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) } | 
						
							| 6 | 1 2 3 4 | efgtf |  |-  ( x e. W -> ( ( T ` x ) = ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) /\ ( T ` x ) : ( ( 0 ... ( # ` x ) ) X. ( I X. 2o ) ) --> W ) ) | 
						
							| 7 | 6 | simpld |  |-  ( x e. W -> ( T ` x ) = ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) ) | 
						
							| 8 | 7 | rneqd |  |-  ( x e. W -> ran ( T ` x ) = ran ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) ) | 
						
							| 9 | 8 | sseq1d |  |-  ( x e. W -> ( ran ( T ` x ) C_ [ x ] r <-> ran ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) C_ [ x ] r ) ) | 
						
							| 10 |  | dfss3 |  |-  ( ran ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) C_ [ x ] r <-> A. a e. ran ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) a e. [ x ] r ) | 
						
							| 11 |  | ovex |  |-  ( x splice <. m , m , <" u ( M ` u ) "> >. ) e. _V | 
						
							| 12 | 11 | rgen2w |  |-  A. m e. ( 0 ... ( # ` x ) ) A. u e. ( I X. 2o ) ( x splice <. m , m , <" u ( M ` u ) "> >. ) e. _V | 
						
							| 13 |  | eqid |  |-  ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) = ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) | 
						
							| 14 |  | vex |  |-  a e. _V | 
						
							| 15 |  | vex |  |-  x e. _V | 
						
							| 16 | 14 15 | elec |  |-  ( a e. [ x ] r <-> x r a ) | 
						
							| 17 |  | breq2 |  |-  ( a = ( x splice <. m , m , <" u ( M ` u ) "> >. ) -> ( x r a <-> x r ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) ) | 
						
							| 18 | 16 17 | bitrid |  |-  ( a = ( x splice <. m , m , <" u ( M ` u ) "> >. ) -> ( a e. [ x ] r <-> x r ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) ) | 
						
							| 19 | 13 18 | ralrnmpo |  |-  ( A. m e. ( 0 ... ( # ` x ) ) A. u e. ( I X. 2o ) ( x splice <. m , m , <" u ( M ` u ) "> >. ) e. _V -> ( A. a e. ran ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) a e. [ x ] r <-> A. m e. ( 0 ... ( # ` x ) ) A. u e. ( I X. 2o ) x r ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) ) | 
						
							| 20 | 12 19 | ax-mp |  |-  ( A. a e. ran ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) a e. [ x ] r <-> A. m e. ( 0 ... ( # ` x ) ) A. u e. ( I X. 2o ) x r ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) | 
						
							| 21 |  | id |  |-  ( u = <. a , b >. -> u = <. a , b >. ) | 
						
							| 22 |  | fveq2 |  |-  ( u = <. a , b >. -> ( M ` u ) = ( M ` <. a , b >. ) ) | 
						
							| 23 |  | df-ov |  |-  ( a M b ) = ( M ` <. a , b >. ) | 
						
							| 24 | 22 23 | eqtr4di |  |-  ( u = <. a , b >. -> ( M ` u ) = ( a M b ) ) | 
						
							| 25 | 21 24 | s2eqd |  |-  ( u = <. a , b >. -> <" u ( M ` u ) "> = <" <. a , b >. ( a M b ) "> ) | 
						
							| 26 | 25 | oteq3d |  |-  ( u = <. a , b >. -> <. m , m , <" u ( M ` u ) "> >. = <. m , m , <" <. a , b >. ( a M b ) "> >. ) | 
						
							| 27 | 26 | oveq2d |  |-  ( u = <. a , b >. -> ( x splice <. m , m , <" u ( M ` u ) "> >. ) = ( x splice <. m , m , <" <. a , b >. ( a M b ) "> >. ) ) | 
						
							| 28 | 27 | breq2d |  |-  ( u = <. a , b >. -> ( x r ( x splice <. m , m , <" u ( M ` u ) "> >. ) <-> x r ( x splice <. m , m , <" <. a , b >. ( a M b ) "> >. ) ) ) | 
						
							| 29 | 28 | ralxp |  |-  ( A. u e. ( I X. 2o ) x r ( x splice <. m , m , <" u ( M ` u ) "> >. ) <-> A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. ( a M b ) "> >. ) ) | 
						
							| 30 |  | eqidd |  |-  ( ( a e. I /\ b e. 2o ) -> <. a , b >. = <. a , b >. ) | 
						
							| 31 | 3 | efgmval |  |-  ( ( a e. I /\ b e. 2o ) -> ( a M b ) = <. a , ( 1o \ b ) >. ) | 
						
							| 32 | 30 31 | s2eqd |  |-  ( ( a e. I /\ b e. 2o ) -> <" <. a , b >. ( a M b ) "> = <" <. a , b >. <. a , ( 1o \ b ) >. "> ) | 
						
							| 33 | 32 | oteq3d |  |-  ( ( a e. I /\ b e. 2o ) -> <. m , m , <" <. a , b >. ( a M b ) "> >. = <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) | 
						
							| 34 | 33 | oveq2d |  |-  ( ( a e. I /\ b e. 2o ) -> ( x splice <. m , m , <" <. a , b >. ( a M b ) "> >. ) = ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) | 
						
							| 35 | 34 | breq2d |  |-  ( ( a e. I /\ b e. 2o ) -> ( x r ( x splice <. m , m , <" <. a , b >. ( a M b ) "> >. ) <-> x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) ) | 
						
							| 36 | 35 | ralbidva |  |-  ( a e. I -> ( A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. ( a M b ) "> >. ) <-> A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) ) | 
						
							| 37 | 36 | ralbiia |  |-  ( A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. ( a M b ) "> >. ) <-> A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) | 
						
							| 38 | 29 37 | bitri |  |-  ( A. u e. ( I X. 2o ) x r ( x splice <. m , m , <" u ( M ` u ) "> >. ) <-> A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) | 
						
							| 39 | 38 | ralbii |  |-  ( A. m e. ( 0 ... ( # ` x ) ) A. u e. ( I X. 2o ) x r ( x splice <. m , m , <" u ( M ` u ) "> >. ) <-> A. m e. ( 0 ... ( # ` x ) ) A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) | 
						
							| 40 | 20 39 | bitri |  |-  ( A. a e. ran ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) a e. [ x ] r <-> A. m e. ( 0 ... ( # ` x ) ) A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) | 
						
							| 41 | 10 40 | bitri |  |-  ( ran ( m e. ( 0 ... ( # ` x ) ) , u e. ( I X. 2o ) |-> ( x splice <. m , m , <" u ( M ` u ) "> >. ) ) C_ [ x ] r <-> A. m e. ( 0 ... ( # ` x ) ) A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) | 
						
							| 42 | 9 41 | bitrdi |  |-  ( x e. W -> ( ran ( T ` x ) C_ [ x ] r <-> A. m e. ( 0 ... ( # ` x ) ) A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) ) | 
						
							| 43 | 42 | ralbiia |  |-  ( A. x e. W ran ( T ` x ) C_ [ x ] r <-> A. x e. W A. m e. ( 0 ... ( # ` x ) ) A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) | 
						
							| 44 | 43 | anbi2i |  |-  ( ( r Er W /\ A. x e. W ran ( T ` x ) C_ [ x ] r ) <-> ( r Er W /\ A. x e. W A. m e. ( 0 ... ( # ` x ) ) A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) ) | 
						
							| 45 | 44 | abbii |  |-  { r | ( r Er W /\ A. x e. W ran ( T ` x ) C_ [ x ] r ) } = { r | ( r Er W /\ A. x e. W A. m e. ( 0 ... ( # ` x ) ) A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) } | 
						
							| 46 | 45 | inteqi |  |-  |^| { r | ( r Er W /\ A. x e. W ran ( T ` x ) C_ [ x ] r ) } = |^| { r | ( r Er W /\ A. x e. W A. m e. ( 0 ... ( # ` x ) ) A. a e. I A. b e. 2o x r ( x splice <. m , m , <" <. a , b >. <. a , ( 1o \ b ) >. "> >. ) ) } | 
						
							| 47 | 5 46 | eqtr4i |  |-  .~ = |^| { r | ( r Er W /\ A. x e. W ran ( T ` x ) C_ [ x ] r ) } |