Hello friends.

A friend of mine is doing research with a professor on the 3 by 3 multivariable case of the Von Neumann inequality. I am helping him out a little bit, but we are running into some techincal problems. For example, what is the quickest way to calculate the operator norm of a contraction matrix? For example what is $\displaystyle \|A\|$ where $\displaystyle A=\frac{1}{2}I_3$?