| Step | Hyp | Ref | Expression | 
						
							| 1 |  | zringbas |  |-  ZZ = ( Base ` ZZring ) | 
						
							| 2 |  | eqid |  |-  ( .g ` ZZring ) = ( .g ` ZZring ) | 
						
							| 3 |  | zsubrg |  |-  ZZ e. ( SubRing ` CCfld ) | 
						
							| 4 |  | subrgsubg |  |-  ( ZZ e. ( SubRing ` CCfld ) -> ZZ e. ( SubGrp ` CCfld ) ) | 
						
							| 5 | 3 4 | ax-mp |  |-  ZZ e. ( SubGrp ` CCfld ) | 
						
							| 6 |  | df-zring |  |-  ZZring = ( CCfld |`s ZZ ) | 
						
							| 7 | 6 | subggrp |  |-  ( ZZ e. ( SubGrp ` CCfld ) -> ZZring e. Grp ) | 
						
							| 8 | 5 7 | mp1i |  |-  ( T. -> ZZring e. Grp ) | 
						
							| 9 |  | 1zzd |  |-  ( T. -> 1 e. ZZ ) | 
						
							| 10 |  | ax-1cn |  |-  1 e. CC | 
						
							| 11 |  | cnfldmulg |  |-  ( ( x e. ZZ /\ 1 e. CC ) -> ( x ( .g ` CCfld ) 1 ) = ( x x. 1 ) ) | 
						
							| 12 | 10 11 | mpan2 |  |-  ( x e. ZZ -> ( x ( .g ` CCfld ) 1 ) = ( x x. 1 ) ) | 
						
							| 13 |  | 1z |  |-  1 e. ZZ | 
						
							| 14 |  | eqid |  |-  ( .g ` CCfld ) = ( .g ` CCfld ) | 
						
							| 15 | 14 6 2 | subgmulg |  |-  ( ( ZZ e. ( SubGrp ` CCfld ) /\ x e. ZZ /\ 1 e. ZZ ) -> ( x ( .g ` CCfld ) 1 ) = ( x ( .g ` ZZring ) 1 ) ) | 
						
							| 16 | 5 13 15 | mp3an13 |  |-  ( x e. ZZ -> ( x ( .g ` CCfld ) 1 ) = ( x ( .g ` ZZring ) 1 ) ) | 
						
							| 17 |  | zcn |  |-  ( x e. ZZ -> x e. CC ) | 
						
							| 18 | 17 | mulridd |  |-  ( x e. ZZ -> ( x x. 1 ) = x ) | 
						
							| 19 | 12 16 18 | 3eqtr3rd |  |-  ( x e. ZZ -> x = ( x ( .g ` ZZring ) 1 ) ) | 
						
							| 20 |  | oveq1 |  |-  ( z = x -> ( z ( .g ` ZZring ) 1 ) = ( x ( .g ` ZZring ) 1 ) ) | 
						
							| 21 | 20 | rspceeqv |  |-  ( ( x e. ZZ /\ x = ( x ( .g ` ZZring ) 1 ) ) -> E. z e. ZZ x = ( z ( .g ` ZZring ) 1 ) ) | 
						
							| 22 | 19 21 | mpdan |  |-  ( x e. ZZ -> E. z e. ZZ x = ( z ( .g ` ZZring ) 1 ) ) | 
						
							| 23 | 22 | adantl |  |-  ( ( T. /\ x e. ZZ ) -> E. z e. ZZ x = ( z ( .g ` ZZring ) 1 ) ) | 
						
							| 24 | 1 2 8 9 23 | iscygd |  |-  ( T. -> ZZring e. CycGrp ) | 
						
							| 25 | 24 | mptru |  |-  ZZring e. CycGrp |