English
The composition with ε equals aeval under the mapped ε: ε ∘ (substAlgHom ha) = aeval (ha.hasEval.map hε).
Русский
Составление с ε равно аeval, применённому к ha.hasEval.map hε: ε ∘ (substAlgHom ha) = aeval (ha.hasEval.map hε).
LaTeX
$$$\\varepsilon \\circ (\\operatorname{substAlgHom}(ha)) = \\operatorname{MvPowerSeries.aeval}(ha.hasEval.map h\\varepsilon)$$$
Lean4
theorem comp_substAlgHom [UniformSpace R] [DiscreteUniformity R] [UniformSpace S] [DiscreteUniformity S]
(ha : HasSubst a) (hε : Continuous ε) : ε.comp (substAlgHom ha) = aeval (ha.hasEval.map hε) :=
by
ext f
simp only [AlgHom.coe_comp, substAlgHom_eq_aeval ha]
exact DFunLike.congr_fun (comp_aeval ha.hasEval hε) f