English
The general composition of two formal multilinear series is defined by summing over all compositions of n.
Русский
Обобщенная композиция формальных много-линейных рядов задается суммой по всем композициям n.
LaTeX
$$$q.comp p = \\sum_{c: \\mathrm{Composition}(n)} q.compAlongComposition p c$$$
Lean4
/-- The `0`-th coefficient of `q.comp p` is `q 0`. When `p` goes from `E` to `E`, this can be
expressed as a direct equality -/
theorem comp_coeff_zero'' (q : FormalMultilinearSeries 𝕜 E F) (p : FormalMultilinearSeries 𝕜 E E) :
(q.comp p) 0 = q 0 := by ext v; exact q.comp_coeff_zero p _ _