Metamath Proof Explorer


Theorem risci

Description: Determine that two rings are isomorphic. (Contributed by Jeff Madsen, 16-Jun-2011)

Ref Expression
Assertion risci ( ( 𝑅 ∈ RingOps ∧ 𝑆 ∈ RingOps ∧ 𝐹 ∈ ( 𝑅 RngIso 𝑆 ) ) → 𝑅𝑟 𝑆 )

Proof

Step Hyp Ref Expression
1 elex2 ( 𝐹 ∈ ( 𝑅 RngIso 𝑆 ) → ∃ 𝑓 𝑓 ∈ ( 𝑅 RngIso 𝑆 ) )
2 risc ( ( 𝑅 ∈ RingOps ∧ 𝑆 ∈ RingOps ) → ( 𝑅𝑟 𝑆 ↔ ∃ 𝑓 𝑓 ∈ ( 𝑅 RngIso 𝑆 ) ) )
3 1 2 syl5ibr ( ( 𝑅 ∈ RingOps ∧ 𝑆 ∈ RingOps ) → ( 𝐹 ∈ ( 𝑅 RngIso 𝑆 ) → 𝑅𝑟 𝑆 ) )
4 3 3impia ( ( 𝑅 ∈ RingOps ∧ 𝑆 ∈ RingOps ∧ 𝐹 ∈ ( 𝑅 RngIso 𝑆 ) ) → 𝑅𝑟 𝑆 )