At 14:20 the dimension formula is more intuitive if stated as dim(S) + dim(U) - dim(S∩U) = dim(S+U)    i.e. " the dimension of S added to the dimension of U minus the dimention of the interscetion of  S and U is the dimension of S+U"  ... so much easier to visualize stated that way n'est-ce pas?####[['dimension formula', 'Mathematical_Related_Concept', 'NEU']]