How to make pipe (vertical bar) symbol to grow like in Dirac product notation but without outer angle brackets?
Usually LaTeX is used with e-TeX that provides
The extra spaces of
If the vertical bar is used like a relational symbol, then the spacing is achieved by
e-TeX does not insert space between a math rel atom and the closing delimiter, the left side of
An alternative is
For a binary operator the space would be
The behaviour is a little closer to a binary operator with the following construct:
Either way, it is a good idea to hide the implementation details in a markup macro.
While it defines only commands that uses angle brackets or braces (for sets), one can easily copy-edit the specification for
Advantages over the very similar solution of Heiko Oberdiek is
You can preface delimiters with
So if you know which side of the bar is bigger, you can try something like this: