| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 2zrng.e |  |-  E = { z e. ZZ | E. x e. ZZ z = ( 2 x. x ) } | 
						
							| 2 |  | 2zrngbas.r |  |-  R = ( CCfld |`s E ) | 
						
							| 3 |  | eqeq1 |  |-  ( z = a -> ( z = ( 2 x. x ) <-> a = ( 2 x. x ) ) ) | 
						
							| 4 | 3 | rexbidv |  |-  ( z = a -> ( E. x e. ZZ z = ( 2 x. x ) <-> E. x e. ZZ a = ( 2 x. x ) ) ) | 
						
							| 5 | 4 1 | elrab2 |  |-  ( a e. E <-> ( a e. ZZ /\ E. x e. ZZ a = ( 2 x. x ) ) ) | 
						
							| 6 |  | eqeq1 |  |-  ( z = b -> ( z = ( 2 x. x ) <-> b = ( 2 x. x ) ) ) | 
						
							| 7 | 6 | rexbidv |  |-  ( z = b -> ( E. x e. ZZ z = ( 2 x. x ) <-> E. x e. ZZ b = ( 2 x. x ) ) ) | 
						
							| 8 | 7 1 | elrab2 |  |-  ( b e. E <-> ( b e. ZZ /\ E. x e. ZZ b = ( 2 x. x ) ) ) | 
						
							| 9 |  | oveq2 |  |-  ( x = y -> ( 2 x. x ) = ( 2 x. y ) ) | 
						
							| 10 | 9 | eqeq2d |  |-  ( x = y -> ( a = ( 2 x. x ) <-> a = ( 2 x. y ) ) ) | 
						
							| 11 | 10 | cbvrexvw |  |-  ( E. x e. ZZ a = ( 2 x. x ) <-> E. y e. ZZ a = ( 2 x. y ) ) | 
						
							| 12 |  | zaddcl |  |-  ( ( a e. ZZ /\ b e. ZZ ) -> ( a + b ) e. ZZ ) | 
						
							| 13 | 12 | ancoms |  |-  ( ( b e. ZZ /\ a e. ZZ ) -> ( a + b ) e. ZZ ) | 
						
							| 14 | 13 | adantr |  |-  ( ( ( b e. ZZ /\ a e. ZZ ) /\ ( E. x e. ZZ b = ( 2 x. x ) /\ E. y e. ZZ a = ( 2 x. y ) ) ) -> ( a + b ) e. ZZ ) | 
						
							| 15 |  | simpl |  |-  ( ( y e. ZZ /\ a = ( 2 x. y ) ) -> y e. ZZ ) | 
						
							| 16 |  | simpl |  |-  ( ( x e. ZZ /\ b = ( 2 x. x ) ) -> x e. ZZ ) | 
						
							| 17 |  | zaddcl |  |-  ( ( y e. ZZ /\ x e. ZZ ) -> ( y + x ) e. ZZ ) | 
						
							| 18 | 15 16 17 | syl2anr |  |-  ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) -> ( y + x ) e. ZZ ) | 
						
							| 19 | 18 | adantr |  |-  ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) -> ( y + x ) e. ZZ ) | 
						
							| 20 |  | oveq2 |  |-  ( z = ( y + x ) -> ( 2 x. z ) = ( 2 x. ( y + x ) ) ) | 
						
							| 21 | 20 | eqeq2d |  |-  ( z = ( y + x ) -> ( ( 2 x. ( y + x ) ) = ( 2 x. z ) <-> ( 2 x. ( y + x ) ) = ( 2 x. ( y + x ) ) ) ) | 
						
							| 22 | 21 | adantl |  |-  ( ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) /\ z = ( y + x ) ) -> ( ( 2 x. ( y + x ) ) = ( 2 x. z ) <-> ( 2 x. ( y + x ) ) = ( 2 x. ( y + x ) ) ) ) | 
						
							| 23 |  | eqidd |  |-  ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) -> ( 2 x. ( y + x ) ) = ( 2 x. ( y + x ) ) ) | 
						
							| 24 | 19 22 23 | rspcedvd |  |-  ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) -> E. z e. ZZ ( 2 x. ( y + x ) ) = ( 2 x. z ) ) | 
						
							| 25 |  | simpr |  |-  ( ( y e. ZZ /\ a = ( 2 x. y ) ) -> a = ( 2 x. y ) ) | 
						
							| 26 |  | simpr |  |-  ( ( x e. ZZ /\ b = ( 2 x. x ) ) -> b = ( 2 x. x ) ) | 
						
							| 27 | 25 26 | oveqan12rd |  |-  ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) -> ( a + b ) = ( ( 2 x. y ) + ( 2 x. x ) ) ) | 
						
							| 28 | 27 | adantr |  |-  ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) -> ( a + b ) = ( ( 2 x. y ) + ( 2 x. x ) ) ) | 
						
							| 29 |  | 2cnd |  |-  ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) -> 2 e. CC ) | 
						
							| 30 |  | zcn |  |-  ( y e. ZZ -> y e. CC ) | 
						
							| 31 | 30 | adantr |  |-  ( ( y e. ZZ /\ a = ( 2 x. y ) ) -> y e. CC ) | 
						
							| 32 | 31 | adantl |  |-  ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) -> y e. CC ) | 
						
							| 33 |  | zcn |  |-  ( x e. ZZ -> x e. CC ) | 
						
							| 34 | 33 | adantr |  |-  ( ( x e. ZZ /\ b = ( 2 x. x ) ) -> x e. CC ) | 
						
							| 35 | 34 | adantr |  |-  ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) -> x e. CC ) | 
						
							| 36 | 29 32 35 | adddid |  |-  ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) -> ( 2 x. ( y + x ) ) = ( ( 2 x. y ) + ( 2 x. x ) ) ) | 
						
							| 37 | 36 | adantr |  |-  ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) -> ( 2 x. ( y + x ) ) = ( ( 2 x. y ) + ( 2 x. x ) ) ) | 
						
							| 38 | 28 37 | eqtr4d |  |-  ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) -> ( a + b ) = ( 2 x. ( y + x ) ) ) | 
						
							| 39 | 38 | eqeq1d |  |-  ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) -> ( ( a + b ) = ( 2 x. z ) <-> ( 2 x. ( y + x ) ) = ( 2 x. z ) ) ) | 
						
							| 40 | 39 | rexbidv |  |-  ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) -> ( E. z e. ZZ ( a + b ) = ( 2 x. z ) <-> E. z e. ZZ ( 2 x. ( y + x ) ) = ( 2 x. z ) ) ) | 
						
							| 41 | 24 40 | mpbird |  |-  ( ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) /\ ( b e. ZZ /\ a e. ZZ ) ) -> E. z e. ZZ ( a + b ) = ( 2 x. z ) ) | 
						
							| 42 | 41 | ex |  |-  ( ( ( x e. ZZ /\ b = ( 2 x. x ) ) /\ ( y e. ZZ /\ a = ( 2 x. y ) ) ) -> ( ( b e. ZZ /\ a e. ZZ ) -> E. z e. ZZ ( a + b ) = ( 2 x. z ) ) ) | 
						
							| 43 | 42 | rexlimdvaa |  |-  ( ( x e. ZZ /\ b = ( 2 x. x ) ) -> ( E. y e. ZZ a = ( 2 x. y ) -> ( ( b e. ZZ /\ a e. ZZ ) -> E. z e. ZZ ( a + b ) = ( 2 x. z ) ) ) ) | 
						
							| 44 | 43 | rexlimiva |  |-  ( E. x e. ZZ b = ( 2 x. x ) -> ( E. y e. ZZ a = ( 2 x. y ) -> ( ( b e. ZZ /\ a e. ZZ ) -> E. z e. ZZ ( a + b ) = ( 2 x. z ) ) ) ) | 
						
							| 45 | 44 | imp |  |-  ( ( E. x e. ZZ b = ( 2 x. x ) /\ E. y e. ZZ a = ( 2 x. y ) ) -> ( ( b e. ZZ /\ a e. ZZ ) -> E. z e. ZZ ( a + b ) = ( 2 x. z ) ) ) | 
						
							| 46 |  | oveq2 |  |-  ( x = z -> ( 2 x. x ) = ( 2 x. z ) ) | 
						
							| 47 | 46 | eqeq2d |  |-  ( x = z -> ( ( a + b ) = ( 2 x. x ) <-> ( a + b ) = ( 2 x. z ) ) ) | 
						
							| 48 | 47 | cbvrexvw |  |-  ( E. x e. ZZ ( a + b ) = ( 2 x. x ) <-> E. z e. ZZ ( a + b ) = ( 2 x. z ) ) | 
						
							| 49 | 45 48 | imbitrrdi |  |-  ( ( E. x e. ZZ b = ( 2 x. x ) /\ E. y e. ZZ a = ( 2 x. y ) ) -> ( ( b e. ZZ /\ a e. ZZ ) -> E. x e. ZZ ( a + b ) = ( 2 x. x ) ) ) | 
						
							| 50 | 49 | impcom |  |-  ( ( ( b e. ZZ /\ a e. ZZ ) /\ ( E. x e. ZZ b = ( 2 x. x ) /\ E. y e. ZZ a = ( 2 x. y ) ) ) -> E. x e. ZZ ( a + b ) = ( 2 x. x ) ) | 
						
							| 51 |  | eqeq1 |  |-  ( z = ( a + b ) -> ( z = ( 2 x. x ) <-> ( a + b ) = ( 2 x. x ) ) ) | 
						
							| 52 | 51 | rexbidv |  |-  ( z = ( a + b ) -> ( E. x e. ZZ z = ( 2 x. x ) <-> E. x e. ZZ ( a + b ) = ( 2 x. x ) ) ) | 
						
							| 53 | 52 1 | elrab2 |  |-  ( ( a + b ) e. E <-> ( ( a + b ) e. ZZ /\ E. x e. ZZ ( a + b ) = ( 2 x. x ) ) ) | 
						
							| 54 | 14 50 53 | sylanbrc |  |-  ( ( ( b e. ZZ /\ a e. ZZ ) /\ ( E. x e. ZZ b = ( 2 x. x ) /\ E. y e. ZZ a = ( 2 x. y ) ) ) -> ( a + b ) e. E ) | 
						
							| 55 | 54 | exp32 |  |-  ( ( b e. ZZ /\ a e. ZZ ) -> ( E. x e. ZZ b = ( 2 x. x ) -> ( E. y e. ZZ a = ( 2 x. y ) -> ( a + b ) e. E ) ) ) | 
						
							| 56 | 55 | impancom |  |-  ( ( b e. ZZ /\ E. x e. ZZ b = ( 2 x. x ) ) -> ( a e. ZZ -> ( E. y e. ZZ a = ( 2 x. y ) -> ( a + b ) e. E ) ) ) | 
						
							| 57 | 56 | com13 |  |-  ( E. y e. ZZ a = ( 2 x. y ) -> ( a e. ZZ -> ( ( b e. ZZ /\ E. x e. ZZ b = ( 2 x. x ) ) -> ( a + b ) e. E ) ) ) | 
						
							| 58 | 11 57 | sylbi |  |-  ( E. x e. ZZ a = ( 2 x. x ) -> ( a e. ZZ -> ( ( b e. ZZ /\ E. x e. ZZ b = ( 2 x. x ) ) -> ( a + b ) e. E ) ) ) | 
						
							| 59 | 58 | impcom |  |-  ( ( a e. ZZ /\ E. x e. ZZ a = ( 2 x. x ) ) -> ( ( b e. ZZ /\ E. x e. ZZ b = ( 2 x. x ) ) -> ( a + b ) e. E ) ) | 
						
							| 60 | 59 | imp |  |-  ( ( ( a e. ZZ /\ E. x e. ZZ a = ( 2 x. x ) ) /\ ( b e. ZZ /\ E. x e. ZZ b = ( 2 x. x ) ) ) -> ( a + b ) e. E ) | 
						
							| 61 | 5 8 60 | syl2anb |  |-  ( ( a e. E /\ b e. E ) -> ( a + b ) e. E ) | 
						
							| 62 | 61 | rgen2 |  |-  A. a e. E A. b e. E ( a + b ) e. E | 
						
							| 63 |  | 0z |  |-  0 e. ZZ | 
						
							| 64 |  | 2cn |  |-  2 e. CC | 
						
							| 65 |  | 0zd |  |-  ( 2 e. CC -> 0 e. ZZ ) | 
						
							| 66 |  | oveq2 |  |-  ( x = 0 -> ( 2 x. x ) = ( 2 x. 0 ) ) | 
						
							| 67 | 66 | eqeq2d |  |-  ( x = 0 -> ( 0 = ( 2 x. x ) <-> 0 = ( 2 x. 0 ) ) ) | 
						
							| 68 | 67 | adantl |  |-  ( ( 2 e. CC /\ x = 0 ) -> ( 0 = ( 2 x. x ) <-> 0 = ( 2 x. 0 ) ) ) | 
						
							| 69 |  | mul01 |  |-  ( 2 e. CC -> ( 2 x. 0 ) = 0 ) | 
						
							| 70 | 69 | eqcomd |  |-  ( 2 e. CC -> 0 = ( 2 x. 0 ) ) | 
						
							| 71 | 65 68 70 | rspcedvd |  |-  ( 2 e. CC -> E. x e. ZZ 0 = ( 2 x. x ) ) | 
						
							| 72 | 64 71 | ax-mp |  |-  E. x e. ZZ 0 = ( 2 x. x ) | 
						
							| 73 |  | eqeq1 |  |-  ( z = 0 -> ( z = ( 2 x. x ) <-> 0 = ( 2 x. x ) ) ) | 
						
							| 74 | 73 | rexbidv |  |-  ( z = 0 -> ( E. x e. ZZ z = ( 2 x. x ) <-> E. x e. ZZ 0 = ( 2 x. x ) ) ) | 
						
							| 75 | 74 | elrab |  |-  ( 0 e. { z e. ZZ | E. x e. ZZ z = ( 2 x. x ) } <-> ( 0 e. ZZ /\ E. x e. ZZ 0 = ( 2 x. x ) ) ) | 
						
							| 76 | 63 72 75 | mpbir2an |  |-  0 e. { z e. ZZ | E. x e. ZZ z = ( 2 x. x ) } | 
						
							| 77 | 76 1 | eleqtrri |  |-  0 e. E | 
						
							| 78 | 1 2 | 2zrngbas |  |-  E = ( Base ` R ) | 
						
							| 79 | 1 2 | 2zrngadd |  |-  + = ( +g ` R ) | 
						
							| 80 | 78 79 | ismgmn0 |  |-  ( 0 e. E -> ( R e. Mgm <-> A. a e. E A. b e. E ( a + b ) e. E ) ) | 
						
							| 81 | 77 80 | ax-mp |  |-  ( R e. Mgm <-> A. a e. E A. b e. E ( a + b ) e. E ) | 
						
							| 82 | 62 81 | mpbir |  |-  R e. Mgm |