Metamath Proof Explorer


Theorem nghmcl

Description: A normed group homomorphism has a real operator norm. (Contributed by Mario Carneiro, 18-Oct-2015)

Ref Expression
Hypothesis nmofval.1 ⊢ N = S normOp T
Assertion nghmcl ⊢ F ∈ S NGHom T → N ⁡ F ∈ ℝ

Proof

Step Hyp Ref Expression
1 nmofval.1 ⊢ N = S normOp T
2 1 isnghm ⊢ F ∈ S NGHom T ↔ S ∈ NrmGrp ∧ T ∈ NrmGrp ∧ F ∈ S GrpHom T ∧ N ⁡ F ∈ ℝ
3 2 simprbi ⊢ F ∈ S NGHom T → F ∈ S GrpHom T ∧ N ⁡ F ∈ ℝ
4 3 simprd ⊢ F ∈ S NGHom T → N ⁡ F ∈ ℝ