In non-relativistic QM, say we are given some observable M and some wave function Ψ. For each unique eigenvalue of M there is at least one corresponding eigenvector. Actually, there can be a multiple (subspace) eigenvectors corresponding to the one eigenvalue. But if we are given a set of distinct eigenvectors to start with, then there is always just one unique eigenvalue for each of those distinct eigenvectors. There are never multiple eigenvalues associated with just one eigenvector. Is that a true statement?