| Step | Hyp | Ref | Expression | 
						
							| 1 |  | fvmpocurryd.f |  |-  F = ( x e. X , y e. Y |-> C ) | 
						
							| 2 |  | fvmpocurryd.c |  |-  ( ph -> A. x e. X A. y e. Y C e. V ) | 
						
							| 3 |  | fvmpocurryd.y |  |-  ( ph -> Y e. W ) | 
						
							| 4 |  | fvmpocurryd.a |  |-  ( ph -> A e. X ) | 
						
							| 5 |  | fvmpocurryd.b |  |-  ( ph -> B e. Y ) | 
						
							| 6 |  | csbcom |  |-  [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C = [_ A / a ]_ [_ B / b ]_ [_ b / y ]_ [_ a / x ]_ C | 
						
							| 7 |  | csbcow |  |-  [_ B / b ]_ [_ b / y ]_ [_ a / x ]_ C = [_ B / y ]_ [_ a / x ]_ C | 
						
							| 8 | 7 | csbeq2i |  |-  [_ A / a ]_ [_ B / b ]_ [_ b / y ]_ [_ a / x ]_ C = [_ A / a ]_ [_ B / y ]_ [_ a / x ]_ C | 
						
							| 9 |  | csbcom |  |-  [_ A / a ]_ [_ B / y ]_ [_ a / x ]_ C = [_ B / y ]_ [_ A / a ]_ [_ a / x ]_ C | 
						
							| 10 |  | csbcow |  |-  [_ A / a ]_ [_ a / x ]_ C = [_ A / x ]_ C | 
						
							| 11 | 10 | csbeq2i |  |-  [_ B / y ]_ [_ A / a ]_ [_ a / x ]_ C = [_ B / y ]_ [_ A / x ]_ C | 
						
							| 12 | 9 11 | eqtri |  |-  [_ A / a ]_ [_ B / y ]_ [_ a / x ]_ C = [_ B / y ]_ [_ A / x ]_ C | 
						
							| 13 | 6 8 12 | 3eqtri |  |-  [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C = [_ B / y ]_ [_ A / x ]_ C | 
						
							| 14 |  | nfcsb1v |  |-  F/_ x [_ A / x ]_ C | 
						
							| 15 | 14 | nfel1 |  |-  F/ x [_ A / x ]_ C e. V | 
						
							| 16 |  | nfcsb1v |  |-  F/_ y [_ B / y ]_ [_ A / x ]_ C | 
						
							| 17 | 16 | nfel1 |  |-  F/ y [_ B / y ]_ [_ A / x ]_ C e. V | 
						
							| 18 |  | csbeq1a |  |-  ( x = A -> C = [_ A / x ]_ C ) | 
						
							| 19 | 18 | eleq1d |  |-  ( x = A -> ( C e. V <-> [_ A / x ]_ C e. V ) ) | 
						
							| 20 |  | csbeq1a |  |-  ( y = B -> [_ A / x ]_ C = [_ B / y ]_ [_ A / x ]_ C ) | 
						
							| 21 | 20 | eleq1d |  |-  ( y = B -> ( [_ A / x ]_ C e. V <-> [_ B / y ]_ [_ A / x ]_ C e. V ) ) | 
						
							| 22 | 15 17 19 21 | rspc2 |  |-  ( ( A e. X /\ B e. Y ) -> ( A. x e. X A. y e. Y C e. V -> [_ B / y ]_ [_ A / x ]_ C e. V ) ) | 
						
							| 23 | 22 | imp |  |-  ( ( ( A e. X /\ B e. Y ) /\ A. x e. X A. y e. Y C e. V ) -> [_ B / y ]_ [_ A / x ]_ C e. V ) | 
						
							| 24 | 4 5 2 23 | syl21anc |  |-  ( ph -> [_ B / y ]_ [_ A / x ]_ C e. V ) | 
						
							| 25 | 13 24 | eqeltrid |  |-  ( ph -> [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C e. V ) | 
						
							| 26 |  | eqid |  |-  ( b e. Y |-> [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) = ( b e. Y |-> [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 27 | 26 | fvmpts |  |-  ( ( B e. Y /\ [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C e. V ) -> ( ( b e. Y |-> [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) ` B ) = [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 28 | 5 25 27 | syl2anc |  |-  ( ph -> ( ( b e. Y |-> [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) ` B ) = [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 29 |  | nfcv |  |-  F/_ a C | 
						
							| 30 |  | nfcv |  |-  F/_ b C | 
						
							| 31 |  | nfcv |  |-  F/_ x b | 
						
							| 32 |  | nfcsb1v |  |-  F/_ x [_ a / x ]_ C | 
						
							| 33 | 31 32 | nfcsbw |  |-  F/_ x [_ b / y ]_ [_ a / x ]_ C | 
						
							| 34 |  | nfcsb1v |  |-  F/_ y [_ b / y ]_ [_ a / x ]_ C | 
						
							| 35 |  | csbeq1a |  |-  ( x = a -> C = [_ a / x ]_ C ) | 
						
							| 36 |  | csbeq1a |  |-  ( y = b -> [_ a / x ]_ C = [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 37 | 35 36 | sylan9eq |  |-  ( ( x = a /\ y = b ) -> C = [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 38 | 29 30 33 34 37 | cbvmpo |  |-  ( x e. X , y e. Y |-> C ) = ( a e. X , b e. Y |-> [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 39 | 1 38 | eqtri |  |-  F = ( a e. X , b e. Y |-> [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 40 | 32 | nfel1 |  |-  F/ x [_ a / x ]_ C e. V | 
						
							| 41 | 34 | nfel1 |  |-  F/ y [_ b / y ]_ [_ a / x ]_ C e. V | 
						
							| 42 | 35 | eleq1d |  |-  ( x = a -> ( C e. V <-> [_ a / x ]_ C e. V ) ) | 
						
							| 43 | 36 | eleq1d |  |-  ( y = b -> ( [_ a / x ]_ C e. V <-> [_ b / y ]_ [_ a / x ]_ C e. V ) ) | 
						
							| 44 | 40 41 42 43 | rspc2 |  |-  ( ( a e. X /\ b e. Y ) -> ( A. x e. X A. y e. Y C e. V -> [_ b / y ]_ [_ a / x ]_ C e. V ) ) | 
						
							| 45 | 2 44 | mpan9 |  |-  ( ( ph /\ ( a e. X /\ b e. Y ) ) -> [_ b / y ]_ [_ a / x ]_ C e. V ) | 
						
							| 46 | 45 | ralrimivva |  |-  ( ph -> A. a e. X A. b e. Y [_ b / y ]_ [_ a / x ]_ C e. V ) | 
						
							| 47 | 5 | ne0d |  |-  ( ph -> Y =/= (/) ) | 
						
							| 48 | 39 46 47 3 4 | mpocurryvald |  |-  ( ph -> ( curry F ` A ) = ( b e. Y |-> [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) ) | 
						
							| 49 | 48 | fveq1d |  |-  ( ph -> ( ( curry F ` A ) ` B ) = ( ( b e. Y |-> [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) ` B ) ) | 
						
							| 50 | 1 | a1i |  |-  ( ph -> F = ( x e. X , y e. Y |-> C ) ) | 
						
							| 51 |  | csbcow |  |-  [_ y / b ]_ [_ b / y ]_ [_ a / x ]_ C = [_ y / y ]_ [_ a / x ]_ C | 
						
							| 52 |  | csbid |  |-  [_ y / y ]_ [_ a / x ]_ C = [_ a / x ]_ C | 
						
							| 53 | 51 52 | eqtr2i |  |-  [_ a / x ]_ C = [_ y / b ]_ [_ b / y ]_ [_ a / x ]_ C | 
						
							| 54 | 53 | a1i |  |-  ( ph -> [_ a / x ]_ C = [_ y / b ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 55 | 54 | csbeq2dv |  |-  ( ph -> [_ x / a ]_ [_ a / x ]_ C = [_ x / a ]_ [_ y / b ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 56 |  | csbcow |  |-  [_ x / a ]_ [_ a / x ]_ C = [_ x / x ]_ C | 
						
							| 57 |  | csbid |  |-  [_ x / x ]_ C = C | 
						
							| 58 | 56 57 | eqtri |  |-  [_ x / a ]_ [_ a / x ]_ C = C | 
						
							| 59 |  | csbcom |  |-  [_ x / a ]_ [_ y / b ]_ [_ b / y ]_ [_ a / x ]_ C = [_ y / b ]_ [_ x / a ]_ [_ b / y ]_ [_ a / x ]_ C | 
						
							| 60 | 55 58 59 | 3eqtr3g |  |-  ( ph -> C = [_ y / b ]_ [_ x / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 61 |  | csbeq1 |  |-  ( x = A -> [_ x / a ]_ [_ b / y ]_ [_ a / x ]_ C = [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 62 | 61 | adantr |  |-  ( ( x = A /\ y = B ) -> [_ x / a ]_ [_ b / y ]_ [_ a / x ]_ C = [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 63 | 62 | csbeq2dv |  |-  ( ( x = A /\ y = B ) -> [_ y / b ]_ [_ x / a ]_ [_ b / y ]_ [_ a / x ]_ C = [_ y / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 64 |  | csbeq1 |  |-  ( y = B -> [_ y / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C = [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 65 | 64 | adantl |  |-  ( ( x = A /\ y = B ) -> [_ y / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C = [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 66 | 63 65 | eqtrd |  |-  ( ( x = A /\ y = B ) -> [_ y / b ]_ [_ x / a ]_ [_ b / y ]_ [_ a / x ]_ C = [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 67 | 60 66 | sylan9eq |  |-  ( ( ph /\ ( x = A /\ y = B ) ) -> C = [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 68 |  | eqidd |  |-  ( ( ph /\ x = A ) -> Y = Y ) | 
						
							| 69 |  | nfv |  |-  F/ x ph | 
						
							| 70 |  | nfv |  |-  F/ y ph | 
						
							| 71 |  | nfcv |  |-  F/_ y A | 
						
							| 72 |  | nfcv |  |-  F/_ x B | 
						
							| 73 |  | nfcv |  |-  F/_ x A | 
						
							| 74 | 73 33 | nfcsbw |  |-  F/_ x [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C | 
						
							| 75 | 72 74 | nfcsbw |  |-  F/_ x [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C | 
						
							| 76 | 13 16 | nfcxfr |  |-  F/_ y [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C | 
						
							| 77 | 50 67 68 4 5 25 69 70 71 72 75 76 | ovmpodxf |  |-  ( ph -> ( A F B ) = [_ B / b ]_ [_ A / a ]_ [_ b / y ]_ [_ a / x ]_ C ) | 
						
							| 78 | 28 49 77 | 3eqtr4d |  |-  ( ph -> ( ( curry F ` A ) ` B ) = ( A F B ) ) |