I am referring to a proof in Part II of Rudin's Functional Analysis.
I got confused by his proof of Thm 6.26 (page 167). He says by applying (2) successively we can get inequality (4), but I do not see how this can be done. If I am right, $T^N$ should be the operator $(D_1D_2D_3\dots D_n)^N$. I do not see how this is related to the $N$-norm of a function.
Can someone elaborate a little bit?
Thanks!