English
A convenient constructor for IsFiltration when the index is the integers: F(n) = F(n-1) for all n.
Русский
Удобный конструктор IsFiltration, когда индекс целые числа: F(n) = F(n-1) для каждого n.
LaTeX
$$$\\text{IsFiltration.mk_int}(F,\\,\\text{mono}) : \\text{IsFiltration } F (n \\mapsto F(n-1))$$$
Lean4
/-- A convenience constructor for `IsFiltration` when the index is the integers. -/
theorem mk_int (F : ℤ → σ) (mono : Monotone F) : IsFiltration F (fun n ↦ F (n - 1))
where
mono := mono
is_le lt := mono (Int.le_sub_one_of_lt lt)
is_sup _ j hi := hi (j - 1) (sub_one_lt j)