Notes for AKT-090924-1/0:07:33

We can also express ${\mathcal {A}}_{n}={\mathcal {D}}_{n}^{0}/b({\mathcal {D}}_{n}^{1})$ where ${\mathcal {D}}_{n}^{0}$ is the v.s. of chord diagrams with $n$ chords, ${\mathcal {D}}_{n}^{1}$ is the v.s. of chord diagrams with one $T$ shape and $(n-2)$ chords and $b$ is the map that takes the $T$ shape to the signed sum of its four resolutions as in the 4T relation.