Metamath Proof Explorer


Theorem pzriprnglem1

Description: Lemma 1 for pzriprng : R is a non-unital (actually a unital!) ring. (Contributed by AV, 17-Mar-2025)

Ref Expression
Hypothesis pzriprng.r ⊢ R = ℤ ring × 𝑠 ℤ ring
Assertion pzriprnglem1 ⊢ R ∈ Rng

Proof

Step Hyp Ref Expression
1 pzriprng.r ⊢ R = ℤ ring × 𝑠 ℤ ring
2 zringrng ⊢ ℤ ring ∈ Rng
3 id ⊢ ℤ ring ∈ Rng → ℤ ring ∈ Rng
4 1 3 3 xpsrngd ⊢ ℤ ring ∈ Rng → R ∈ Rng
5 2 4 ax-mp ⊢ R ∈ Rng