Frequently Asked Question List for TeX

It was long thought impossible to make a `proof`

environment which automatically includes an “end-of-proof” symbol.
Some proofs end in displayed maths; others do not. If the input file
contains
`...\] \end{proof}`

then LaTeX finishes off
the displayed maths and gets ready for a new line before it reads any
instructions connected with ending the proof, so the code is very
tricky. You *can* insert the symbol by hand, but the
(apparently) original “automatic” solution came with Paul Taylor’s
`QED`

.

Nowadays, the `ntheorem`

package now solves the problem for
LaTeX users: it provides an automatic way of signalling
the end of a proof.

The AMSLaTeX package `amsthm`

also provides a
`proof`

environment that does the job; though you need to
insert a `\qedhere`

command if the proof ends with a displayed
equation:

```
\begin{proof}
text...
\begin{equation*}
maths... \tag*{\qedhere}
\end{equation*}
\end{proof}
```

The `\tag*{`

\qedhere`}`

construction may be used in any of
AMSLaTeX’s numbering environments.