Ramana Kumar comments on Sub-Sums and Sub-Tensors

[Ramana Kumar]

In the first claim of 3.4, the last bit of the claim is $D^{\prime }\in C_0⊞C_1$ but the proof actually shows $D^{\prime }\in C_0^{\prime }⊞C_1^{\prime }$.

[Scott Garrabrant]

Fixed, thanks. The proof was right, and the original claim was trivial.