Metamath Proof Explorer


Theorem qrng1

Description: The unit element of the field of rationals. (Contributed by Mario Carneiro, 8-Sep-2014)

Ref Expression
Hypothesis qrng.q
|- Q = ( CCfld |`s QQ )
Assertion qrng1
|- 1 = ( 1r ` Q )

Proof

Step Hyp Ref Expression
1 qrng.q
 |-  Q = ( CCfld |`s QQ )
2 qsubdrg
 |-  ( QQ e. ( SubRing ` CCfld ) /\ ( CCfld |`s QQ ) e. DivRing )
3 2 simpli
 |-  QQ e. ( SubRing ` CCfld )
4 cnfld1
 |-  1 = ( 1r ` CCfld )
5 1 4 subrg1
 |-  ( QQ e. ( SubRing ` CCfld ) -> 1 = ( 1r ` Q ) )
6 3 5 ax-mp
 |-  1 = ( 1r ` Q )