Metamath Proof Explorer


Theorem fldcrng

Description: A field is a commutative ring. (Contributed by Jeff Madsen, 8-Jun-2010)

Ref Expression
Assertion fldcrng ( 𝐾 ∈ Fld → 𝐾 ∈ CRingOps )

Proof

Step Hyp Ref Expression
1 eqid ( 1st𝐾 ) = ( 1st𝐾 )
2 eqid ( 2nd𝐾 ) = ( 2nd𝐾 )
3 eqid ran ( 1st𝐾 ) = ran ( 1st𝐾 )
4 eqid ( GId ‘ ( 1st𝐾 ) ) = ( GId ‘ ( 1st𝐾 ) )
5 1 2 3 4 drngoi ( 𝐾 ∈ DivRingOps → ( 𝐾 ∈ RingOps ∧ ( ( 2nd𝐾 ) ↾ ( ( ran ( 1st𝐾 ) ∖ { ( GId ‘ ( 1st𝐾 ) ) } ) × ( ran ( 1st𝐾 ) ∖ { ( GId ‘ ( 1st𝐾 ) ) } ) ) ) ∈ GrpOp ) )
6 5 simpld ( 𝐾 ∈ DivRingOps → 𝐾 ∈ RingOps )
7 6 anim1i ( ( 𝐾 ∈ DivRingOps ∧ 𝐾 ∈ Com2 ) → ( 𝐾 ∈ RingOps ∧ 𝐾 ∈ Com2 ) )
8 df-fld Fld = ( DivRingOps ∩ Com2 )
9 8 elin2 ( 𝐾 ∈ Fld ↔ ( 𝐾 ∈ DivRingOps ∧ 𝐾 ∈ Com2 ) )
10 iscrngo ( 𝐾 ∈ CRingOps ↔ ( 𝐾 ∈ RingOps ∧ 𝐾 ∈ Com2 ) )
11 7 9 10 3imtr4i ( 𝐾 ∈ Fld → 𝐾 ∈ CRingOps )