English
If F1 and F2 are IsCyclotomicExtension for n1 and n2, then the lcm sup in the intermediate field lattice yields an IsCyclotomicExtension for n1.lcm n2.
Русский
Если F1 и F2 являются IsCyclotomicExtension для n1 и n2, то верхняя граница по НСН lcm в решетке промежуточных полей образует IsCyclotomicExtension для n1.lcm n2.
LaTeX
$$$\\text{IsCyclotomicExtension}(\\{n_1\\}\\!) \\Rightarrow \\text{IsCyclotomicExtension}(\\operatorname{lcm}(n_1,n_2))$ в соответствующем контексте$$
Lean4
theorem isCyclotomicExtension_lcm_sup [NeZero n₁] [NeZero n₂] :
IsCyclotomicExtension {n₁.lcm n₂} K (F₁ ⊔ F₂ : IntermediateField K L) :=
by
have : FiniteDimensional K F₁ := IsCyclotomicExtension.finite_of_singleton n₁ K F₁
have := IsCyclotomicExtension.lcm_sup n₁ n₂ F₁.toSubalgebra F₂.toSubalgebra
rwa [← sup_toSubalgebra_of_left] at this