| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							rrx2xpreen.r | 
							 |-  R = ( RR ^m { 1 , 2 } ) | 
						
						
							| 2 | 
							
								
							 | 
							rrx2xpref1o.1 | 
							 |-  F = ( x e. RR , y e. RR |-> { <. 1 , x >. , <. 2 , y >. } ) | 
						
						
							| 3 | 
							
								
							 | 
							prex | 
							 |-  { <. 1 , x >. , <. 2 , y >. } e. _V | 
						
						
							| 4 | 
							
								2 3
							 | 
							fnmpoi | 
							 |-  F Fn ( RR X. RR )  | 
						
						
							| 5 | 
							
								
							 | 
							1st2nd2 | 
							 |-  ( z e. ( RR X. RR ) -> z = <. ( 1st ` z ) , ( 2nd ` z ) >. )  | 
						
						
							| 6 | 
							
								5
							 | 
							fveq2d | 
							 |-  ( z e. ( RR X. RR ) -> ( F ` z ) = ( F ` <. ( 1st ` z ) , ( 2nd ` z ) >. ) )  | 
						
						
							| 7 | 
							
								
							 | 
							df-ov | 
							 |-  ( ( 1st ` z ) F ( 2nd ` z ) ) = ( F ` <. ( 1st ` z ) , ( 2nd ` z ) >. )  | 
						
						
							| 8 | 
							
								6 7
							 | 
							eqtr4di | 
							 |-  ( z e. ( RR X. RR ) -> ( F ` z ) = ( ( 1st ` z ) F ( 2nd ` z ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							xp1st | 
							 |-  ( z e. ( RR X. RR ) -> ( 1st ` z ) e. RR )  | 
						
						
							| 10 | 
							
								
							 | 
							xp2nd | 
							 |-  ( z e. ( RR X. RR ) -> ( 2nd ` z ) e. RR )  | 
						
						
							| 11 | 
							
								
							 | 
							opeq2 | 
							 |-  ( x = ( 1st ` z ) -> <. 1 , x >. = <. 1 , ( 1st ` z ) >. )  | 
						
						
							| 12 | 
							
								11
							 | 
							preq1d | 
							 |-  ( x = ( 1st ` z ) -> { <. 1 , x >. , <. 2 , y >. } = { <. 1 , ( 1st ` z ) >. , <. 2 , y >. } ) | 
						
						
							| 13 | 
							
								
							 | 
							opeq2 | 
							 |-  ( y = ( 2nd ` z ) -> <. 2 , y >. = <. 2 , ( 2nd ` z ) >. )  | 
						
						
							| 14 | 
							
								13
							 | 
							preq2d | 
							 |-  ( y = ( 2nd ` z ) -> { <. 1 , ( 1st ` z ) >. , <. 2 , y >. } = { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } ) | 
						
						
							| 15 | 
							
								
							 | 
							prex | 
							 |-  { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } e. _V | 
						
						
							| 16 | 
							
								12 14 2 15
							 | 
							ovmpo | 
							 |-  ( ( ( 1st ` z ) e. RR /\ ( 2nd ` z ) e. RR ) -> ( ( 1st ` z ) F ( 2nd ` z ) ) = { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } ) | 
						
						
							| 17 | 
							
								9 10 16
							 | 
							syl2anc | 
							 |-  ( z e. ( RR X. RR ) -> ( ( 1st ` z ) F ( 2nd ` z ) ) = { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } ) | 
						
						
							| 18 | 
							
								8 17
							 | 
							eqtrd | 
							 |-  ( z e. ( RR X. RR ) -> ( F ` z ) = { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } ) | 
						
						
							| 19 | 
							
								
							 | 
							eqid | 
							 |-  { 1 , 2 } = { 1 , 2 } | 
						
						
							| 20 | 
							
								19 1
							 | 
							prelrrx2 | 
							 |-  ( ( ( 1st ` z ) e. RR /\ ( 2nd ` z ) e. RR ) -> { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } e. R ) | 
						
						
							| 21 | 
							
								9 10 20
							 | 
							syl2anc | 
							 |-  ( z e. ( RR X. RR ) -> { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } e. R ) | 
						
						
							| 22 | 
							
								18 21
							 | 
							eqeltrd | 
							 |-  ( z e. ( RR X. RR ) -> ( F ` z ) e. R )  | 
						
						
							| 23 | 
							
								22
							 | 
							rgen | 
							 |-  A. z e. ( RR X. RR ) ( F ` z ) e. R  | 
						
						
							| 24 | 
							
								
							 | 
							ffnfv | 
							 |-  ( F : ( RR X. RR ) --> R <-> ( F Fn ( RR X. RR ) /\ A. z e. ( RR X. RR ) ( F ` z ) e. R ) )  | 
						
						
							| 25 | 
							
								4 23 24
							 | 
							mpbir2an | 
							 |-  F : ( RR X. RR ) --> R  | 
						
						
							| 26 | 
							
								
							 | 
							opex | 
							 |-  <. 1 , ( 1st ` z ) >. e. _V  | 
						
						
							| 27 | 
							
								
							 | 
							opex | 
							 |-  <. 2 , ( 2nd ` z ) >. e. _V  | 
						
						
							| 28 | 
							
								
							 | 
							opex | 
							 |-  <. 1 , ( 1st ` w ) >. e. _V  | 
						
						
							| 29 | 
							
								
							 | 
							opex | 
							 |-  <. 2 , ( 2nd ` w ) >. e. _V  | 
						
						
							| 30 | 
							
								26 27 28 29
							 | 
							preq12b | 
							 |-  ( { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } = { <. 1 , ( 1st ` w ) >. , <. 2 , ( 2nd ` w ) >. } <-> ( ( <. 1 , ( 1st ` z ) >. = <. 1 , ( 1st ` w ) >. /\ <. 2 , ( 2nd ` z ) >. = <. 2 , ( 2nd ` w ) >. ) \/ ( <. 1 , ( 1st ` z ) >. = <. 2 , ( 2nd ` w ) >. /\ <. 2 , ( 2nd ` z ) >. = <. 1 , ( 1st ` w ) >. ) ) ) | 
						
						
							| 31 | 
							
								
							 | 
							1ex | 
							 |-  1 e. _V  | 
						
						
							| 32 | 
							
								
							 | 
							fvex | 
							 |-  ( 1st ` z ) e. _V  | 
						
						
							| 33 | 
							
								31 32
							 | 
							opth | 
							 |-  ( <. 1 , ( 1st ` z ) >. = <. 1 , ( 1st ` w ) >. <-> ( 1 = 1 /\ ( 1st ` z ) = ( 1st ` w ) ) )  | 
						
						
							| 34 | 
							
								33
							 | 
							simprbi | 
							 |-  ( <. 1 , ( 1st ` z ) >. = <. 1 , ( 1st ` w ) >. -> ( 1st ` z ) = ( 1st ` w ) )  | 
						
						
							| 35 | 
							
								
							 | 
							2ex | 
							 |-  2 e. _V  | 
						
						
							| 36 | 
							
								
							 | 
							fvex | 
							 |-  ( 2nd ` z ) e. _V  | 
						
						
							| 37 | 
							
								35 36
							 | 
							opth | 
							 |-  ( <. 2 , ( 2nd ` z ) >. = <. 2 , ( 2nd ` w ) >. <-> ( 2 = 2 /\ ( 2nd ` z ) = ( 2nd ` w ) ) )  | 
						
						
							| 38 | 
							
								37
							 | 
							simprbi | 
							 |-  ( <. 2 , ( 2nd ` z ) >. = <. 2 , ( 2nd ` w ) >. -> ( 2nd ` z ) = ( 2nd ` w ) )  | 
						
						
							| 39 | 
							
								34 38
							 | 
							anim12i | 
							 |-  ( ( <. 1 , ( 1st ` z ) >. = <. 1 , ( 1st ` w ) >. /\ <. 2 , ( 2nd ` z ) >. = <. 2 , ( 2nd ` w ) >. ) -> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) )  | 
						
						
							| 40 | 
							
								39
							 | 
							a1d | 
							 |-  ( ( <. 1 , ( 1st ` z ) >. = <. 1 , ( 1st ` w ) >. /\ <. 2 , ( 2nd ` z ) >. = <. 2 , ( 2nd ` w ) >. ) -> ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) ) )  | 
						
						
							| 41 | 
							
								31 32
							 | 
							opth | 
							 |-  ( <. 1 , ( 1st ` z ) >. = <. 2 , ( 2nd ` w ) >. <-> ( 1 = 2 /\ ( 1st ` z ) = ( 2nd ` w ) ) )  | 
						
						
							| 42 | 
							
								35 36
							 | 
							opth | 
							 |-  ( <. 2 , ( 2nd ` z ) >. = <. 1 , ( 1st ` w ) >. <-> ( 2 = 1 /\ ( 2nd ` z ) = ( 1st ` w ) ) )  | 
						
						
							| 43 | 
							
								
							 | 
							1ne2 | 
							 |-  1 =/= 2  | 
						
						
							| 44 | 
							
								
							 | 
							eqneqall | 
							 |-  ( 1 = 2 -> ( 1 =/= 2 -> ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) ) ) )  | 
						
						
							| 45 | 
							
								43 44
							 | 
							mpi | 
							 |-  ( 1 = 2 -> ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) ) )  | 
						
						
							| 46 | 
							
								45
							 | 
							ad2antrr | 
							 |-  ( ( ( 1 = 2 /\ ( 1st ` z ) = ( 2nd ` w ) ) /\ ( 2 = 1 /\ ( 2nd ` z ) = ( 1st ` w ) ) ) -> ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) ) )  | 
						
						
							| 47 | 
							
								41 42 46
							 | 
							syl2anb | 
							 |-  ( ( <. 1 , ( 1st ` z ) >. = <. 2 , ( 2nd ` w ) >. /\ <. 2 , ( 2nd ` z ) >. = <. 1 , ( 1st ` w ) >. ) -> ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) ) )  | 
						
						
							| 48 | 
							
								40 47
							 | 
							jaoi | 
							 |-  ( ( ( <. 1 , ( 1st ` z ) >. = <. 1 , ( 1st ` w ) >. /\ <. 2 , ( 2nd ` z ) >. = <. 2 , ( 2nd ` w ) >. ) \/ ( <. 1 , ( 1st ` z ) >. = <. 2 , ( 2nd ` w ) >. /\ <. 2 , ( 2nd ` z ) >. = <. 1 , ( 1st ` w ) >. ) ) -> ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) ) )  | 
						
						
							| 49 | 
							
								30 48
							 | 
							sylbi | 
							 |-  ( { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } = { <. 1 , ( 1st ` w ) >. , <. 2 , ( 2nd ` w ) >. } -> ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) ) ) | 
						
						
							| 50 | 
							
								49
							 | 
							com12 | 
							 |-  ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } = { <. 1 , ( 1st ` w ) >. , <. 2 , ( 2nd ` w ) >. } -> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) ) ) | 
						
						
							| 51 | 
							
								
							 | 
							1st2nd2 | 
							 |-  ( w e. ( RR X. RR ) -> w = <. ( 1st ` w ) , ( 2nd ` w ) >. )  | 
						
						
							| 52 | 
							
								51
							 | 
							fveq2d | 
							 |-  ( w e. ( RR X. RR ) -> ( F ` w ) = ( F ` <. ( 1st ` w ) , ( 2nd ` w ) >. ) )  | 
						
						
							| 53 | 
							
								
							 | 
							df-ov | 
							 |-  ( ( 1st ` w ) F ( 2nd ` w ) ) = ( F ` <. ( 1st ` w ) , ( 2nd ` w ) >. )  | 
						
						
							| 54 | 
							
								52 53
							 | 
							eqtr4di | 
							 |-  ( w e. ( RR X. RR ) -> ( F ` w ) = ( ( 1st ` w ) F ( 2nd ` w ) ) )  | 
						
						
							| 55 | 
							
								
							 | 
							xp1st | 
							 |-  ( w e. ( RR X. RR ) -> ( 1st ` w ) e. RR )  | 
						
						
							| 56 | 
							
								
							 | 
							xp2nd | 
							 |-  ( w e. ( RR X. RR ) -> ( 2nd ` w ) e. RR )  | 
						
						
							| 57 | 
							
								
							 | 
							opeq2 | 
							 |-  ( x = ( 1st ` w ) -> <. 1 , x >. = <. 1 , ( 1st ` w ) >. )  | 
						
						
							| 58 | 
							
								57
							 | 
							preq1d | 
							 |-  ( x = ( 1st ` w ) -> { <. 1 , x >. , <. 2 , y >. } = { <. 1 , ( 1st ` w ) >. , <. 2 , y >. } ) | 
						
						
							| 59 | 
							
								
							 | 
							opeq2 | 
							 |-  ( y = ( 2nd ` w ) -> <. 2 , y >. = <. 2 , ( 2nd ` w ) >. )  | 
						
						
							| 60 | 
							
								59
							 | 
							preq2d | 
							 |-  ( y = ( 2nd ` w ) -> { <. 1 , ( 1st ` w ) >. , <. 2 , y >. } = { <. 1 , ( 1st ` w ) >. , <. 2 , ( 2nd ` w ) >. } ) | 
						
						
							| 61 | 
							
								
							 | 
							prex | 
							 |-  { <. 1 , ( 1st ` w ) >. , <. 2 , ( 2nd ` w ) >. } e. _V | 
						
						
							| 62 | 
							
								58 60 2 61
							 | 
							ovmpo | 
							 |-  ( ( ( 1st ` w ) e. RR /\ ( 2nd ` w ) e. RR ) -> ( ( 1st ` w ) F ( 2nd ` w ) ) = { <. 1 , ( 1st ` w ) >. , <. 2 , ( 2nd ` w ) >. } ) | 
						
						
							| 63 | 
							
								55 56 62
							 | 
							syl2anc | 
							 |-  ( w e. ( RR X. RR ) -> ( ( 1st ` w ) F ( 2nd ` w ) ) = { <. 1 , ( 1st ` w ) >. , <. 2 , ( 2nd ` w ) >. } ) | 
						
						
							| 64 | 
							
								54 63
							 | 
							eqtrd | 
							 |-  ( w e. ( RR X. RR ) -> ( F ` w ) = { <. 1 , ( 1st ` w ) >. , <. 2 , ( 2nd ` w ) >. } ) | 
						
						
							| 65 | 
							
								18 64
							 | 
							eqeqan12d | 
							 |-  ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( ( F ` z ) = ( F ` w ) <-> { <. 1 , ( 1st ` z ) >. , <. 2 , ( 2nd ` z ) >. } = { <. 1 , ( 1st ` w ) >. , <. 2 , ( 2nd ` w ) >. } ) ) | 
						
						
							| 66 | 
							
								5 51
							 | 
							eqeqan12d | 
							 |-  ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( z = w <-> <. ( 1st ` z ) , ( 2nd ` z ) >. = <. ( 1st ` w ) , ( 2nd ` w ) >. ) )  | 
						
						
							| 67 | 
							
								32 36
							 | 
							opth | 
							 |-  ( <. ( 1st ` z ) , ( 2nd ` z ) >. = <. ( 1st ` w ) , ( 2nd ` w ) >. <-> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) )  | 
						
						
							| 68 | 
							
								66 67
							 | 
							bitrdi | 
							 |-  ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( z = w <-> ( ( 1st ` z ) = ( 1st ` w ) /\ ( 2nd ` z ) = ( 2nd ` w ) ) ) )  | 
						
						
							| 69 | 
							
								50 65 68
							 | 
							3imtr4d | 
							 |-  ( ( z e. ( RR X. RR ) /\ w e. ( RR X. RR ) ) -> ( ( F ` z ) = ( F ` w ) -> z = w ) )  | 
						
						
							| 70 | 
							
								69
							 | 
							rgen2 | 
							 |-  A. z e. ( RR X. RR ) A. w e. ( RR X. RR ) ( ( F ` z ) = ( F ` w ) -> z = w )  | 
						
						
							| 71 | 
							
								
							 | 
							dff13 | 
							 |-  ( F : ( RR X. RR ) -1-1-> R <-> ( F : ( RR X. RR ) --> R /\ A. z e. ( RR X. RR ) A. w e. ( RR X. RR ) ( ( F ` z ) = ( F ` w ) -> z = w ) ) )  | 
						
						
							| 72 | 
							
								25 70 71
							 | 
							mpbir2an | 
							 |-  F : ( RR X. RR ) -1-1-> R  | 
						
						
							| 73 | 
							
								1
							 | 
							eleq2i | 
							 |-  ( w e. R <-> w e. ( RR ^m { 1 , 2 } ) ) | 
						
						
							| 74 | 
							
								
							 | 
							reex | 
							 |-  RR e. _V  | 
						
						
							| 75 | 
							
								
							 | 
							prex | 
							 |-  { 1 , 2 } e. _V | 
						
						
							| 76 | 
							
								74 75
							 | 
							elmap | 
							 |-  ( w e. ( RR ^m { 1 , 2 } ) <-> w : { 1 , 2 } --> RR ) | 
						
						
							| 77 | 
							
								
							 | 
							1re | 
							 |-  1 e. RR  | 
						
						
							| 78 | 
							
								
							 | 
							2re | 
							 |-  2 e. RR  | 
						
						
							| 79 | 
							
								
							 | 
							fpr2g | 
							 |-  ( ( 1 e. RR /\ 2 e. RR ) -> ( w : { 1 , 2 } --> RR <-> ( ( w ` 1 ) e. RR /\ ( w ` 2 ) e. RR /\ w = { <. 1 , ( w ` 1 ) >. , <. 2 , ( w ` 2 ) >. } ) ) ) | 
						
						
							| 80 | 
							
								77 78 79
							 | 
							mp2an | 
							 |-  ( w : { 1 , 2 } --> RR <-> ( ( w ` 1 ) e. RR /\ ( w ` 2 ) e. RR /\ w = { <. 1 , ( w ` 1 ) >. , <. 2 , ( w ` 2 ) >. } ) ) | 
						
						
							| 81 | 
							
								73 76 80
							 | 
							3bitri | 
							 |-  ( w e. R <-> ( ( w ` 1 ) e. RR /\ ( w ` 2 ) e. RR /\ w = { <. 1 , ( w ` 1 ) >. , <. 2 , ( w ` 2 ) >. } ) ) | 
						
						
							| 82 | 
							
								
							 | 
							opeq2 | 
							 |-  ( u = ( w ` 1 ) -> <. 1 , u >. = <. 1 , ( w ` 1 ) >. )  | 
						
						
							| 83 | 
							
								82
							 | 
							preq1d | 
							 |-  ( u = ( w ` 1 ) -> { <. 1 , u >. , <. 2 , v >. } = { <. 1 , ( w ` 1 ) >. , <. 2 , v >. } ) | 
						
						
							| 84 | 
							
								83
							 | 
							eqeq2d | 
							 |-  ( u = ( w ` 1 ) -> ( w = { <. 1 , u >. , <. 2 , v >. } <-> w = { <. 1 , ( w ` 1 ) >. , <. 2 , v >. } ) ) | 
						
						
							| 85 | 
							
								
							 | 
							opeq2 | 
							 |-  ( v = ( w ` 2 ) -> <. 2 , v >. = <. 2 , ( w ` 2 ) >. )  | 
						
						
							| 86 | 
							
								85
							 | 
							preq2d | 
							 |-  ( v = ( w ` 2 ) -> { <. 1 , ( w ` 1 ) >. , <. 2 , v >. } = { <. 1 , ( w ` 1 ) >. , <. 2 , ( w ` 2 ) >. } ) | 
						
						
							| 87 | 
							
								86
							 | 
							eqeq2d | 
							 |-  ( v = ( w ` 2 ) -> ( w = { <. 1 , ( w ` 1 ) >. , <. 2 , v >. } <-> w = { <. 1 , ( w ` 1 ) >. , <. 2 , ( w ` 2 ) >. } ) ) | 
						
						
							| 88 | 
							
								84 87
							 | 
							rspc2ev | 
							 |-  ( ( ( w ` 1 ) e. RR /\ ( w ` 2 ) e. RR /\ w = { <. 1 , ( w ` 1 ) >. , <. 2 , ( w ` 2 ) >. } ) -> E. u e. RR E. v e. RR w = { <. 1 , u >. , <. 2 , v >. } ) | 
						
						
							| 89 | 
							
								81 88
							 | 
							sylbi | 
							 |-  ( w e. R -> E. u e. RR E. v e. RR w = { <. 1 , u >. , <. 2 , v >. } ) | 
						
						
							| 90 | 
							
								
							 | 
							opeq2 | 
							 |-  ( x = u -> <. 1 , x >. = <. 1 , u >. )  | 
						
						
							| 91 | 
							
								90
							 | 
							preq1d | 
							 |-  ( x = u -> { <. 1 , x >. , <. 2 , y >. } = { <. 1 , u >. , <. 2 , y >. } ) | 
						
						
							| 92 | 
							
								
							 | 
							opeq2 | 
							 |-  ( y = v -> <. 2 , y >. = <. 2 , v >. )  | 
						
						
							| 93 | 
							
								92
							 | 
							preq2d | 
							 |-  ( y = v -> { <. 1 , u >. , <. 2 , y >. } = { <. 1 , u >. , <. 2 , v >. } ) | 
						
						
							| 94 | 
							
								
							 | 
							prex | 
							 |-  { <. 1 , u >. , <. 2 , v >. } e. _V | 
						
						
							| 95 | 
							
								91 93 2 94
							 | 
							ovmpo | 
							 |-  ( ( u e. RR /\ v e. RR ) -> ( u F v ) = { <. 1 , u >. , <. 2 , v >. } ) | 
						
						
							| 96 | 
							
								95
							 | 
							eqeq2d | 
							 |-  ( ( u e. RR /\ v e. RR ) -> ( w = ( u F v ) <-> w = { <. 1 , u >. , <. 2 , v >. } ) ) | 
						
						
							| 97 | 
							
								96
							 | 
							2rexbiia | 
							 |-  ( E. u e. RR E. v e. RR w = ( u F v ) <-> E. u e. RR E. v e. RR w = { <. 1 , u >. , <. 2 , v >. } ) | 
						
						
							| 98 | 
							
								89 97
							 | 
							sylibr | 
							 |-  ( w e. R -> E. u e. RR E. v e. RR w = ( u F v ) )  | 
						
						
							| 99 | 
							
								
							 | 
							fveq2 | 
							 |-  ( z = <. u , v >. -> ( F ` z ) = ( F ` <. u , v >. ) )  | 
						
						
							| 100 | 
							
								
							 | 
							df-ov | 
							 |-  ( u F v ) = ( F ` <. u , v >. )  | 
						
						
							| 101 | 
							
								99 100
							 | 
							eqtr4di | 
							 |-  ( z = <. u , v >. -> ( F ` z ) = ( u F v ) )  | 
						
						
							| 102 | 
							
								101
							 | 
							eqeq2d | 
							 |-  ( z = <. u , v >. -> ( w = ( F ` z ) <-> w = ( u F v ) ) )  | 
						
						
							| 103 | 
							
								102
							 | 
							rexxp | 
							 |-  ( E. z e. ( RR X. RR ) w = ( F ` z ) <-> E. u e. RR E. v e. RR w = ( u F v ) )  | 
						
						
							| 104 | 
							
								98 103
							 | 
							sylibr | 
							 |-  ( w e. R -> E. z e. ( RR X. RR ) w = ( F ` z ) )  | 
						
						
							| 105 | 
							
								104
							 | 
							rgen | 
							 |-  A. w e. R E. z e. ( RR X. RR ) w = ( F ` z )  | 
						
						
							| 106 | 
							
								
							 | 
							dffo3 | 
							 |-  ( F : ( RR X. RR ) -onto-> R <-> ( F : ( RR X. RR ) --> R /\ A. w e. R E. z e. ( RR X. RR ) w = ( F ` z ) ) )  | 
						
						
							| 107 | 
							
								25 105 106
							 | 
							mpbir2an | 
							 |-  F : ( RR X. RR ) -onto-> R  | 
						
						
							| 108 | 
							
								
							 | 
							df-f1o | 
							 |-  ( F : ( RR X. RR ) -1-1-onto-> R <-> ( F : ( RR X. RR ) -1-1-> R /\ F : ( RR X. RR ) -onto-> R ) )  | 
						
						
							| 109 | 
							
								72 107 108
							 | 
							mpbir2an | 
							 |-  F : ( RR X. RR ) -1-1-onto-> R  |