Graph Signal Processing, Gsp, Signal Processing, Spectral Analysis, Fourier Transform.
given by g-hat(λl) (The term on the left-hand side of the equation above). The following expression is the product of the value of graph signal at i-th vertex and the value of the l-th eigenvector at the i-th vertex. Doing the above product for all vertices from 1 to N and taking the sum will give