Lp Subspaces

I've been given an assignment question, where I've been asked to identify $L_P[-n, n]$ as a subpsace of $L_p(\mathbb R)$ in the obvious way. It seems to me though that this may be backwards, as if $f \in L_p( \mathbb R)$ then its p-power should also be integrable on any subspace of $\mathbb R$. However, a function integrable on [-n,n] may not be p-power integrable on all of R. Do I have this backwards?

Hurkyl
Staff Emeritus