The question I am trying to answer is as follows

Let F={(a,b): 0<a, b<7}$\displaystyle \subset$ . Show that H^{s}(F)=0 if s>2, 0<H^{2}(F)<$\displaystyle \infty$ and H^{s}(F) = $\displaystyle \infty$ if s<2. (You may need to use the fact that if U is a subset of , then the area of U is at most equation to |U|^{2}x $\displaystyle \pi$/4

I have managed to show H^{s}(F)=0 if s>2 but showing 0<H^{2}(F)<$\displaystyle \infty$ if s<2 I do not know how to do or even get started.

Any help greatfully appreciated