Recently. the Lanczos bidiagonalization method over tensor space has been proposed for computing the maximum and minimum singular values of a tensor sum T. The method over tensor space is practical in memory and has a simple implementation due to recent developments in tensor computations; however. there is still room for improvement in the convergence to the minimum singular value. https://www.marcelovicente.com/product-category/vitamino-color-10-in-1-milk/