English
The completion of a composition equals the composition of completions: g.completion ∘ f.completion = (g ∘ f).completion.
Русский
Завершение композиции равно композиции завершений: g^{comp} ∘ f^{comp} = (g ∘ f)^{comp}.
LaTeX
$$$ g^{\mathrm{comp}} \circ f^{\mathrm{comp}} = (g \circ f)^{\mathrm{comp}}.$$$
Lean4
theorem completion_comp (f : NormedAddGroupHom G H) (g : NormedAddGroupHom H K) :
g.completion.comp f.completion = (g.comp f).completion :=
by
ext x
rw [NormedAddGroupHom.coe_comp, NormedAddGroupHom.completion_def, NormedAddGroupHom.completion_coe_to_fun,
NormedAddGroupHom.completion_coe_to_fun, Completion.map_comp g.uniformContinuous f.uniformContinuous]
rfl