# Have a question about $L^p$ multiplier.

I'm studying $L^p$ multiplier. While reading the book, it says

"The characteristic function of the unit disk is not an $L^p$ multiplier on $\mathbb{R}^n$ when $n\ge2$ unless $p=2$."

How can I verify this? It says it will be discussed in later section 10.1 which does not exist, the book ends at Chapter 5. There is no section 10.1.

• Perhaps you could mention the title of the book. Jan 27 '15 at 15:42
• It's Classical fourier analysis - Loukas Grafakos 2ed. Jan 27 '15 at 15:44
• Section 10.1 is here Jan 27 '15 at 15:56
• The book Classical Fourier Analysis indeed has only 5 chapters. But it has continuation called Modern Fourier Analysis, which has chapter 10. (Both books belong are from Graduate Texts in Mathematics series.) Jan 28 '15 at 9:50