English
If m is a maximal ideal in a Noetherian ring R and R is IsAdicComplete with respect to m, then R is a local ring.
Русский
Если m — максимальный идеал в Нётеровом кольце R и R является IsAdicComplete по m, тогда R локально.
LaTeX
$$$$ IsLocalRing\ R $$$$
Lean4
theorem isLocalRing_of_isAdicComplete_maximal [IsAdicComplete m R] : IsLocalRing R
where
exists_pair_ne := ⟨0, 1, ne_of_mem_of_not_mem m.zero_mem (m.ne_top_iff_one.mp (Ideal.IsMaximal.ne_top hmax))⟩
isUnit_or_isUnit_of_add_one {a b}
hab := by
simp only [isUnit_iff_notMem_of_isAdicComplete_maximal m]
by_contra! h
absurd m.add_mem h.1 h.2
simpa [hab] using m.ne_top_iff_one.mp (Ideal.IsMaximal.ne_top hmax)