Graph Signal Processing, Fourier Transform, Graph Fourier Transform, Eigenvectors, Spectral Analysis.
eigenvectors are the Fourier modes. Read through [6] and [9] if you need to convince yourself of this. Then we can write the circulant matrix Ac in terms of the DFT matrix as follows. Decomposing circulant matrix Ac in terms of DFT matrix Comparing this form with the eigendecomposition of matrix A