# Phantom not working as expected in cases environment

They do, but since you have aligned the two lines with & the space on left does not matter.

If you want the "Case" example to be aligned you have to add {} because + is a binary operator and Latex adds space between an operator and its arguments. Hence if there is no argument, as in your case, then no space is added.

```
\documentclass{amsart}
\[
\begin{cases}
M+A+T & =12\\
\phantom{M+{}}A+T & =10
\end{cases}
\]
\end{document}
```

Hope I could help :)

Technically it does; it's the alignment difference between `align`

and `cases`

that's tripping you up. `align`

has a RIGHT-LEFT alignment for elements around `&`

, while `cases`

has a LEFT-LEFT alignment. As such, the spacing shows (more) clearly in `cases`

than `align`

.

To achieve the proper spacing, using `\phantom{M + {}}`

- add an empty group after `+`

to ensure TeX sees it as a *binary* operator.

```
\documentclass{amsart}
\begin{document}
\begin{align*}
M + A + T & = 12 \\
\phantom{M + {}} A + T & = 10
\end{align*}
\[
\begin{cases}
M + A + T & = 12 \\
\phantom{M + {}} A + T & = 10
\end{cases}
\]
\end{document}
```

You are probably better off using the following `cases`

:

```
\[
\begin{cases}
M + A + T = 12 \\
\phantom{M + {}} A + T = 10
\end{cases}
\]
```

The difference is that `align`

makes a pair of columns, one right aligned and one left aligned, so the `\phantom`

does nothing in the case of `align`

or `align*`

.

In order to get the correct spacing you need an empty group: `\phantom{M+{}}`

, because only in this way TeX will consider `+`

as a binary operation symbol.

However there's a simpler solution:

```
\begin{cases}
\begin{aligned}[t]
M+A+T &= 12
A+T &= 10
\end{aligned}
\end{cases}
```

Full comparison:

```
\documentclass{amsart}
\begin{document}
\[
\begin{cases}
M+A+T = 12\\
\phantom{M+{}}A+T = 10
\end{cases}
\]
\[
\begin{cases}
\begin{aligned}[t]
M+A+T &= 12\\
A+T &= 10
\end{aligned}
\end{cases}
\]
\end{document}
```