English
Reiterates that unshift followed by shift returns the original p, affirming the compatibility of these two operations.
Русский
Повторяет, что последовательность действий unshift затем shift возвращает исходный p, подтверждая совместимость операций.
LaTeX
$$$(\\mathrm{shift}(\\mathrm{unshift}(p,z))) = p$$$
Lean4
/-- The index of the first non-zero coefficient in `p` (or `0` if all coefficients are zero). This
is the order of the isolated zero of an analytic function `f` at a point if `p` is the Taylor
series of `f` at that point. -/
noncomputable def order (p : FormalMultilinearSeries 𝕜 E F) : ℕ :=
sInf {n | p n ≠ 0}