Minimal polynomial of a graph

356 Views Asked by At

I would like to know why the minimal polynomial of a graph $G$ is $m(x) = \prod(x-λ_i)$ where the product is taken over all distinct eigenvalues $λ_i$.

1

There are 1 best solutions below

0
On

That's because the adjacency matrix of an undirected graph is symmetric, thus diagonalizable. That means that every irreducible factor of minimal polynomial has multiplicity one.