English
For a surjective f with ker f ≤ jacobson R M, comap f (jacobson R₂ M₂) = jacobson R M.
Русский
Для сюръективного f с ker f ≤ jacobson(R,M) выполняется comap f (jacobson R₂ M₂) = jacobson R M.
LaTeX
$$comap f (jacobson R₂ M₂) = jacobson R M$$
Lean4
theorem le_comap_jacobson : jacobson R M ≤ comap f (jacobson R₂ M₂) :=
by
conv_rhs => rw [jacobson, sInf_eq_iInf', comap_iInf]
refine le_iInf_iff.mpr fun S m hm ↦ ?_
obtain h | h := isCoatom_comap_or_eq_top f S.2
· exact mem_sInf.mp hm _ h
· simpa only [h] using mem_top