I have a little problem, and hope, with your help, I'll be able to solve it.

As you got from the title, I have some trouble with TeX in Mathematica. Imagine, I want to output a nice DisplayFormula, such that it would represent a function, which evaluates piecewise. In TeX it would look like this (Let's take a uniform distribution for example)

$$\left\{ \begin{aligned} &0,& t\leq x_{\min} \\ &\frac{t-x_{\min}}{x_{\max}-x_{\min}},&x_{\min}<t\leq x_{\max} \\ &1,& t>x_{\max} \end{aligned} \right.$$

So what's the best way to create that exact output in Mathematica?

I've tried TraditionalForm[CDF[UniformDistribution[{x_ {min}, x_ {max}}], t]], but that gives me almost the same output, but without the zero part.

enter image description here

I do know, it's not significant whether to write or not the 0 part in the piecewise function.

So it works well for CDF, but with PDF there's an extraneous part is shown at the end


enter image description here

So in the CDF Mathematica's decided not to output the 0 part, but in the PDF it's shown.

I've also tried to use

   {{0, t <= Subscript[x, min]},
    {(t - Subscript[x, min])/(Subscript[x, max] - Subscript[x, min]), 
     Subscript[x, min] < t <= Subscript[x, max]},
    {1, t > Subscript[x, max]}},

But that variant also reveals the part that I haven't specified.

enter image description here

The last thing I've tried to use is ToExpression["TeX source",TeXForm], but this one can't parse the simple TeX source with aligned environment (or I haven't found a way to make it work).


If you just want the output, well, write it manually. EscpwEsc gives you the piecewise bracket. Then you can insert a table (Insert->Table/Matrix) or learn the shortcuts with Ctrl, and CtrlReturn, etc.

I got this box structure. You can see the result by running.

    GridBox[{{RowBox[{"0", ","}], 
       RowBox[{"t", "\[LessEqual]", 
         SubscriptBox["x", "min"]}]}, {RowBox[{FractionBox[
          RowBox[{"t", "-", SubscriptBox["x", "min"]}], 
          RowBox[{SubscriptBox["x", "max"], "-", 
            SubscriptBox["x", "min"]}]], ","}], 
       RowBox[{SubscriptBox["x", "min"], "<", "t", "\[LessEqual]", 
         SubscriptBox["x", "max"]}]}, {RowBox[{"1", ","}], 
       RowBox[{"t", ">", SubscriptBox["x", "max"]}]}}]}], 

You can then style it further to suit you...

  • $\begingroup$ You're correct! Thank you. $\endgroup$ – Sergey Aganezov jr Apr 23 '12 at 6:11

You could use the \[AligmentMarker] character. To help you better write equations, lets forget about the DisplayFormula style and lets create our own.

Set up:

Let us create the style DisplayMath. In your notebook where you are writing your displayed equation go to Format > Edit Stylesheet.... Here you will create a new cell. Show the expression of the cell by going to Cell > Show Expression or by pressing commandshifte in a mac. Now enter the following in that expression:

        "TeX" -> {"$$\n", Convert`TeX`BoxesToTeX[#]& , "\n$$"}, 
        "HTML" -> {"$$\n", StringReplace[Convert`TeX`BoxesToTeX[#], {"<" -> " \\lt ", ">" -> " \\gt "}]& , "\n$$\n\n"}
        "Columns" -> {{"\[AlignmentMarker]"}}, "ColumnsIndexed" -> {}, 
        "Rows" -> {{Baseline}}, "RowsIndexed" -> {}}

This is the style that I'm using to display mathematics. Notice the use of ShowInvisibleCharacters, this makes the \[AligmentMarker] to be displayed. If you do not wish for this to be displayed when you print or in a presentation then turn it off when you use another environment. You do so by creating a cell with these contents:

Cell[StyleData["DisplayMath", "Printout"],

The option GridBoxOptions simply say that the grids in this style will be aligned using the \[AlignmentMarker]. Now lets type some math.

Writing Aligned Equations:

Start by creating a cell using the DisplayMath style, you can do this by pressing command0 in a mac use alt in windows and entering DisplayMath. Enter a+b+c=d. What we want now is to go one step down, we can do this by pressing controlreturn. If you did this now you should see a box right below "d", we want a box to be below the whole expression. So delete that box, select the whole expression and try again. After that enter the following: c=d-a-b. This is what you should see now:

not aligned

To make them become aligned, now we can use the \[AligmentMarker]. We want them to be aligned along the equal signs we can enter EscamEsc next to the equal signs. Now we should see this:


After you finish with a column, you can create another column by pressing control,. And repeat. Here is a display of your equation from your example:


To put the bracket I used what Rojo mentioned. I typed EscpwEsc at the beginning of the equation.


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