In class we learned about convergence rate of the Power Method, which is
$$\kappa = \frac{|\lambda_2|}{|\lambda_1|}$$
if $|\lambda_1| > |\lambda_2| \geq |\lambda_3| ...$ $and$ $\lambda_1$ has a algebraic multiplicity of 1.
Now an exercise wants us to discuss the convergence rate of a matrix with the Inverse Power Method (without shift).
I only found this formula for convergence rate for the Inverse Power Method with shift $\widetilde{\lambda}$:
$$\kappa = \frac{|\lambda_1 - \widetilde{\lambda}|}{|\lambda_2 - \widetilde{\lambda}|}$$
with $\lambda_1$ being the closest eigenvalue (of A?) to $\widetilde{\lambda}$ and $\lambda_2$ the second-closest eigenvalue to $\widetilde{\lambda}$.
So what is the convergence rate of the Inverse Power Method without shift?