Solution
= Solution
By the <Phase classification of the SLE trace>, chordal <SLE> is a <simple curve> for
$$
\boxed{0\leq\kappa\leq4.}
$$
If the convention restricts the notation to $\kappa>0$, the range is $0<\kappa\leq4$. The degenerate case $\kappa=0$ is a deterministic vertical slit and is simple as well.