English
Comultiplication on a basis element in MonoidAlgebra: comul(single x a) = map (lsingle x) (lsingle x) (comul a).
Русский
Копупликация базисного элемента MonoidAlgebra: comul(single x a) = map (lsingle x) (lsingle x) (comul a).
LaTeX
$$$\mathrm{comul}(\mathrm{single}(x,a)) = \big(\mathrm{TensorProduct.map}(\mathrm{lsingle}(x), \mathrm{lsingle}(x))\big)(\mathrm{comul}(a))$$$
Lean4
@[simp]
theorem comul_single (x : X) (a : A) :
Coalgebra.comul (R := R) (single x a) = TensorProduct.map (lsingle x) (lsingle x) (Coalgebra.comul a) :=
Finsupp.comul_single _ _ _ _ _