# Break it down into matrices

I want to break this equation into several matrices multiplied it would be useful to use DFT matrices $$\tilde{H}_{\nu,k}=\frac{1}{N}\sum_{n=0}^{N-1}\sum_{l=0}^{L-1}h_{n,l}e^{-j\frac{2\pi kl}{N}}e^{j\frac{2\pi n}{N}(k-\nu+\epsilon_k)}$$ $\epsilon_k=k\eta+\epsilon_\eta$

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$$\sum_{i,j=1}^n a_{ij} x_i y_j = x^\mathrm T Ay$$