Notes for AKT-091013/0:41:59

Fact 3: Given ${\mathcal {G}}_{1},\ {\mathcal {G}}_{2},\ \ {\mathcal {T}}_{{\mathcal {G}}_{1}}\otimes {\mathcal {T}}_{{\mathcal {G}}_{2}}\circ \Box ={\mathcal {T}}_{{\mathcal {G}}_{1}\oplus {\mathcal {G}}_{2}}$ under the canonical isomorphism.