Metamath Proof Explorer


Theorem rngo0cl

Description: Obsolete theorem, use ring0cl instead. A ring has an additive identity element. (Contributed by Steve Rodriguez, 9-Sep-2007) (New usage is discouraged.) (Proof modification is discouraged.)

Ref Expression
Hypotheses ring0cl.1 ⊢ G = 1 st ⁡ R
ring0cl.2 ⊢ X = ran ⁡ G
ring0cl.3 ⊢ Z = GId ⁡ G
Assertion rngo0cl ⊢ R ∈ RingOps → Z ∈ X

Proof

Step Hyp Ref Expression
1 ring0cl.1 ⊢ G = 1 st ⁡ R
2 ring0cl.2 ⊢ X = ran ⁡ G
3 ring0cl.3 ⊢ Z = GId ⁡ G
4 1 rngogrpo ⊢ R ∈ RingOps → G ∈ GrpOp
5 2 3 grpoidcl ⊢ G ∈ GrpOp → Z ∈ X
6 4 5 syl ⊢ R ∈ RingOps → Z ∈ X