Metamath Proof Explorer


Theorem bddnghm

Description: A bounded group homomorphism is a normed group homomorphism. (Contributed by Mario Carneiro, 18-Oct-2015)

Ref Expression
Hypothesis nmofval.1 ⊢ N = S normOp T
Assertion bddnghm ⊢ S ∈ NrmGrp ∧ T ∈ NrmGrp ∧ F ∈ S GrpHom T ∧ A ∈ ℝ ∧ N ⁡ F ≤ A → F ∈ S NGHom T

Proof

Step Hyp Ref Expression
1 nmofval.1 ⊢ N = S normOp T
2 1 nmocl ⊢ S ∈ NrmGrp ∧ T ∈ NrmGrp ∧ F ∈ S GrpHom T → N ⁡ F ∈ ℝ *
3 1 nmoge0 ⊢ S ∈ NrmGrp ∧ T ∈ NrmGrp ∧ F ∈ S GrpHom T → 0 ≤ N ⁡ F
4 2 3 jca ⊢ S ∈ NrmGrp ∧ T ∈ NrmGrp ∧ F ∈ S GrpHom T → N ⁡ F ∈ ℝ * ∧ 0 ≤ N ⁡ F
5 xrrege0 ⊢ N ⁡ F ∈ ℝ * ∧ A ∈ ℝ ∧ 0 ≤ N ⁡ F ∧ N ⁡ F ≤ A → N ⁡ F ∈ ℝ
6 5 an4s ⊢ N ⁡ F ∈ ℝ * ∧ 0 ≤ N ⁡ F ∧ A ∈ ℝ ∧ N ⁡ F ≤ A → N ⁡ F ∈ ℝ
7 4 6 sylan ⊢ S ∈ NrmGrp ∧ T ∈ NrmGrp ∧ F ∈ S GrpHom T ∧ A ∈ ℝ ∧ N ⁡ F ≤ A → N ⁡ F ∈ ℝ
8 1 isnghm2 ⊢ S ∈ NrmGrp ∧ T ∈ NrmGrp ∧ F ∈ S GrpHom T → F ∈ S NGHom T ↔ N ⁡ F ∈ ℝ
9 8 adantr ⊢ S ∈ NrmGrp ∧ T ∈ NrmGrp ∧ F ∈ S GrpHom T ∧ A ∈ ℝ ∧ N ⁡ F ≤ A → F ∈ S NGHom T ↔ N ⁡ F ∈ ℝ
10 7 9 mpbird ⊢ S ∈ NrmGrp ∧ T ∈ NrmGrp ∧ F ∈ S GrpHom T ∧ A ∈ ℝ ∧ N ⁡ F ≤ A → F ∈ S NGHom T