English
The counit composed with the inr injection from B into A × B is equal to the counit on B; this equality holds by simplifications.
Русский
Коунит, композиция с инр-вставкой из B в A × B, равен коуниту B; равенство следует из упрощений.
LaTeX
$$$ \operatorname{counit} \circ \mathrm{inr}_{R,A,B} = \operatorname{counit} $$$
Lean4
instance instCoalgebraStruct : CoalgebraStruct R (Π₀ i, A i)
where
comul := DFinsupp.lsum R fun i => TensorProduct.map (DFinsupp.lsingle i) (DFinsupp.lsingle i) ∘ₗ comul
counit := DFinsupp.lsum R fun _ => counit