| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cnnrg |  |-  CCfld e. NrmRing | 
						
							| 2 |  | resubdrg |  |-  ( RR e. ( SubRing ` CCfld ) /\ RRfld e. DivRing ) | 
						
							| 3 | 2 | simpli |  |-  RR e. ( SubRing ` CCfld ) | 
						
							| 4 |  | df-refld |  |-  RRfld = ( CCfld |`s RR ) | 
						
							| 5 | 4 | subrgnrg |  |-  ( ( CCfld e. NrmRing /\ RR e. ( SubRing ` CCfld ) ) -> RRfld e. NrmRing ) | 
						
							| 6 | 1 3 5 | mp2an |  |-  RRfld e. NrmRing | 
						
							| 7 | 2 | simpri |  |-  RRfld e. DivRing | 
						
							| 8 | 6 7 | pm3.2i |  |-  ( RRfld e. NrmRing /\ RRfld e. DivRing ) | 
						
							| 9 |  | rezh |  |-  ( ZMod ` RRfld ) e. NrmMod | 
						
							| 10 |  | reofld |  |-  RRfld e. oField | 
						
							| 11 |  | ofldchr |  |-  ( RRfld e. oField -> ( chr ` RRfld ) = 0 ) | 
						
							| 12 | 10 11 | ax-mp |  |-  ( chr ` RRfld ) = 0 | 
						
							| 13 | 9 12 | pm3.2i |  |-  ( ( ZMod ` RRfld ) e. NrmMod /\ ( chr ` RRfld ) = 0 ) | 
						
							| 14 |  | recusp |  |-  RRfld e. CUnifSp | 
						
							| 15 |  | reust |  |-  ( UnifSt ` RRfld ) = ( metUnif ` ( ( dist ` RRfld ) |` ( RR X. RR ) ) ) | 
						
							| 16 | 14 15 | pm3.2i |  |-  ( RRfld e. CUnifSp /\ ( UnifSt ` RRfld ) = ( metUnif ` ( ( dist ` RRfld ) |` ( RR X. RR ) ) ) ) | 
						
							| 17 |  | rebase |  |-  RR = ( Base ` RRfld ) | 
						
							| 18 |  | eqid |  |-  ( ( dist ` RRfld ) |` ( RR X. RR ) ) = ( ( dist ` RRfld ) |` ( RR X. RR ) ) | 
						
							| 19 |  | eqid |  |-  ( ZMod ` RRfld ) = ( ZMod ` RRfld ) | 
						
							| 20 | 17 18 19 | isrrext |  |-  ( RRfld e. RRExt <-> ( ( RRfld e. NrmRing /\ RRfld e. DivRing ) /\ ( ( ZMod ` RRfld ) e. NrmMod /\ ( chr ` RRfld ) = 0 ) /\ ( RRfld e. CUnifSp /\ ( UnifSt ` RRfld ) = ( metUnif ` ( ( dist ` RRfld ) |` ( RR X. RR ) ) ) ) ) ) | 
						
							| 21 | 8 13 16 20 | mpbir3an |  |-  RRfld e. RRExt |