I think the class starts to get messy from 18:30, with occasional clarity, prof. Strang starts to throw out facts that do not have a clear logical connections. For example, the introduction of upper Hessenberg, tri-diagonal and bi-diagonal, why we look for them and in what way do they help QR methods are not very natural to me.####[['prof. Strang', 'Instructor', 'NEG']]