Possible Duplicate:
Does $|x|^p$ with $0satisfy the triangular inequality on $\mathbb{R}$?
Is the function
$f(t)= t^{\alpha},\quad \alpha\in (0,1)$
a subadditive function?
My teacher said categorically that this is true. But I'm not so sure.
EDIT: $~~~~~0\leq t\leq 1$