Metamath Proof Explorer


Theorem frlmlmod

Description: The free module is a module. (Contributed by Stefan O'Rear, 1-Feb-2015)

Ref Expression
Hypothesis frlmval.f ⊢ F = R freeLMod I
Assertion frlmlmod ⊢ R ∈ Ring ∧ I ∈ W → F ∈ LMod

Proof

Step Hyp Ref Expression
1 frlmval.f ⊢ F = R freeLMod I
2 1 frlmval ⊢ R ∈ Ring ∧ I ∈ W → F = R ⊕ m I × ringLMod ⁡ R
3 simpr ⊢ R ∈ Ring ∧ I ∈ W → I ∈ W
4 simpl ⊢ R ∈ Ring ∧ I ∈ W → R ∈ Ring
5 rlmlmod ⊢ R ∈ Ring → ringLMod ⁡ R ∈ LMod
6 5 adantr ⊢ R ∈ Ring ∧ I ∈ W → ringLMod ⁡ R ∈ LMod
7 fconst6g ⊢ ringLMod ⁡ R ∈ LMod → I × ringLMod ⁡ R : I ⟶ LMod
8 6 7 syl ⊢ R ∈ Ring ∧ I ∈ W → I × ringLMod ⁡ R : I ⟶ LMod
9 fvex ⊢ ringLMod ⁡ R ∈ V
10 9 fvconst2 ⊢ i ∈ I → I × ringLMod ⁡ R ⁡ i = ringLMod ⁡ R
11 10 adantl ⊢ R ∈ Ring ∧ I ∈ W ∧ i ∈ I → I × ringLMod ⁡ R ⁡ i = ringLMod ⁡ R
12 11 fveq2d ⊢ R ∈ Ring ∧ I ∈ W ∧ i ∈ I → Scalar ⁡ I × ringLMod ⁡ R ⁡ i = Scalar ⁡ ringLMod ⁡ R
13 rlmsca ⊢ R ∈ Ring → R = Scalar ⁡ ringLMod ⁡ R
14 13 ad2antrr ⊢ R ∈ Ring ∧ I ∈ W ∧ i ∈ I → R = Scalar ⁡ ringLMod ⁡ R
15 12 14 eqtr4d ⊢ R ∈ Ring ∧ I ∈ W ∧ i ∈ I → Scalar ⁡ I × ringLMod ⁡ R ⁡ i = R
16 eqid ⊢ R ⊕ m I × ringLMod ⁡ R = R ⊕ m I × ringLMod ⁡ R
17 3 4 8 15 16 dsmmlmod ⊢ R ∈ Ring ∧ I ∈ W → R ⊕ m I × ringLMod ⁡ R ∈ LMod
18 2 17 eqeltrd ⊢ R ∈ Ring ∧ I ∈ W → F ∈ LMod