i think he breaks with the usual convention for m * n Matrix being: m rows, n collums ... which confused me, but great lecture anyways ...edit: I was wrong9:12 ... misunderstood what he said there, ofc the columspace has m (rows many) components, because colums go m (rows-many) components down ... thanks Robert Smits####[['Robert Smits', 'Instructor', 'POS'], ['m * n Matrix', 'Mathematical_Related_Concept', 'NEU']]