Wikipedia claims that
"Given an n×n matrix A.... both algebraic and geometric multiplicity are integers between (including) 1 and n."
But how can the geometric multiplicity possibly be n? Since $(A-\lambda I)$ is a square matrix (as opposed to a matrix with more columns than rows), each of A's eigenspaces $Nul (A-\lambda I)$ has at most $(n-1)$ dimensions, isn't it?
I.e. The geometric multiplicity of an eigenvalue must be a number between between $1$ and $(n-1)$, right?