And vice versa. Take a graph, write it down as a matrix, apply a discrete Laplacian operator. Then - just as an example - find the number of distinct non-negati

And vice versa. Take a graph, write it down as a matrix, apply a discrete Laplacian operator. Then - just as an example - find the number of distinct non-negative eigenvalues. This is exactly the number of connected components in the graph. Pure magic.