Metamath Proof Explorer


Theorem subrngsubg

Description: A subring is a subgroup. (Contributed by AV, 14-Feb-2025)

Ref Expression
Assertion subrngsubg ⊢ A ∈ SubRng ⁡ R → A ∈ SubGrp ⁡ R

Proof

Step Hyp Ref Expression
1 subrngrcl ⊢ A ∈ SubRng ⁡ R → R ∈ Rng
2 rnggrp ⊢ R ∈ Rng → R ∈ Grp
3 1 2 syl ⊢ A ∈ SubRng ⁡ R → R ∈ Grp
4 eqid ⊢ Base R = Base R
5 4 subrngss ⊢ A ∈ SubRng ⁡ R → A ⊆ Base R
6 eqid ⊢ R ↾ 𝑠 A = R ↾ 𝑠 A
7 6 subrngrng ⊢ A ∈ SubRng ⁡ R → R ↾ 𝑠 A ∈ Rng
8 rnggrp ⊢ R ↾ 𝑠 A ∈ Rng → R ↾ 𝑠 A ∈ Grp
9 7 8 syl ⊢ A ∈ SubRng ⁡ R → R ↾ 𝑠 A ∈ Grp
10 4 issubg ⊢ A ∈ SubGrp ⁡ R ↔ R ∈ Grp ∧ A ⊆ Base R ∧ R ↾ 𝑠 A ∈ Grp
11 3 5 9 10 syl3anbrc ⊢ A ∈ SubRng ⁡ R → A ∈ SubGrp ⁡ R