4. Given the equation about $x$: $|(x-1)(x-3)|=m x$ has four distinct real roots, then the range of values for $m$ is $\qquad$
Given $y=-x^{2}+4 x-3$ and its tangent line $y=k x$, let $A\left(x_{0},-x_{0}^{2}+4 x_{0}-3\right), k=-2 x_{0}+4$, then the tangent line $l: y=\left(-2 x_{0}+4\right)\left(x-x_{0}\right)-x_{0}^{2}+4 x_{0}-3$. Thus, $x_{0}^{2}-3=0 \Rightarrow x_{0}=\sqrt{3} \Rightarrow k=4-2 \sqrt{3}$. From the graph, the range of $m$ is $(0,4-2 \sqrt{3})$.