Metamath Proof Explorer


Theorem pwsgrp

Description: A structure power of a group is a group. (Contributed by Mario Carneiro, 11-Jan-2015)

Ref Expression
Hypothesis pwsgrp.y ⊢ Y = R ↑ 𝑠 I
Assertion pwsgrp ⊢ R ∈ Grp ∧ I ∈ V → Y ∈ Grp

Proof

Step Hyp Ref Expression
1 pwsgrp.y ⊢ Y = R ↑ 𝑠 I
2 eqid ⊢ Scalar ⁡ R = Scalar ⁡ R
3 1 2 pwsval ⊢ R ∈ Grp ∧ I ∈ V → Y = Scalar ⁡ R ⨉ 𝑠 I × R
4 eqid ⊢ Scalar ⁡ R ⨉ 𝑠 I × R = Scalar ⁡ R ⨉ 𝑠 I × R
5 simpr ⊢ R ∈ Grp ∧ I ∈ V → I ∈ V
6 fvexd ⊢ R ∈ Grp ∧ I ∈ V → Scalar ⁡ R ∈ V
7 fconst6g ⊢ R ∈ Grp → I × R : I ⟶ Grp
8 7 adantr ⊢ R ∈ Grp ∧ I ∈ V → I × R : I ⟶ Grp
9 4 5 6 8 prdsgrpd ⊢ R ∈ Grp ∧ I ∈ V → Scalar ⁡ R ⨉ 𝑠 I × R ∈ Grp
10 3 9 eqeltrd ⊢ R ∈ Grp ∧ I ∈ V → Y ∈ Grp