feat(RingTheory/Coalgebra/Convolution): (f ⊗ₘ g) * (h ⊗ₘ k) = (f * h) ⊗ₘ (g * k) (#31251)
(f ⊗ₘ g) * (h ⊗ₘ k) = (f * h) ⊗ₘ (g * k)