I successfully find
exp = CDF[TransformedDistribution[
x1/(x1 + x2 + x3),
{
x1 \[Distributed] UniformDistribution[{0, 1}],
x2 \[Distributed] UniformDistribution[{0, 1}],
x3 \[Distributed] UniformDistribution[{0, 1}]
}
], t]
Then I copy the output as LaTeX and obtain
$$\begin{array}{cc} \{ & \begin{array}{cc} 1 & t>1 \\ -\frac{t}{t-1} & 0<t\leq \frac{1}{3} \\ \frac{5 t^2+2 t-1}{6 t^2} & \frac{1}{2}<t\leq 1 \\ \frac{21 t^3-27 t^2+9 t-1}{6 (t-1) t^2} & \frac{1}{3}<t\leq \frac{1}{2} \\ \end{array} \\ \end{array} $$
The result is not so good. On the other hand,
exp // TeXForm
returns
$$\begin{cases} 1 & t>1 \\ -\frac{t}{t-1} & 0<t\leq \frac{1}{3} \\ \frac{5 t^2+2 t-1}{6 t^2} & \frac{1}{2}<t\leq 1 \\ \frac{21 t^3-27 t^2+9 t-1}{6 (t-1) t^2} & \frac{1}{3}<t\leq \frac{1}{2} \end{cases} $$
which is better. The questions arise: Why is the difference in the outputs observed? Can it be treated as a bug?
GridBox
—basically the same thing what you get when you use Copy As. The typeset version is just a "table" (a grid) without any meaning. The only reason it can even be converted back to a meaningful expression is theTagBox
around it with the"Piecewise"
marker. $\endgroup$TeXForm@DisplayForm@First@ToBoxes[exp]
still gives thecases
version (the correct one), even though we manually removed theTagBox
. So my hunch about what is happening may be wrong. Please do report it to Wolfram. $\endgroup$