# how to typeset empty inner product

I want to typeset the following in TeX (without the arguments).

< , >

I know that I can accomplish this by doing \langle , \rangle

As an example I want to write something like the follwing:

...The adjoints are with respect to the ( \langle , \rangle ) and not with respect to ( ( , ) )

But spacing on either side of the comma inside \langle \rangle does not look right.

How does one fix this? Thanks.

• $\langle {,} \rangle$ ? – David Carlisle Oct 22 '14 at 16:26
• $\langle\,,\rangle$, or what I prefer, \langle\cdot,\cdot\rangle. – yo' Oct 22 '14 at 16:27
• Or even \langle\,\cdot\,,\,\cdot\,\rangle. – Manuel Oct 22 '14 at 16:34
• @Manuel the space after the comma is sure an extra one ;) (there already is one, see my answer). – yo' Oct 22 '14 at 16:36
• @tohecz Definetly, I forgot it :) – Manuel Oct 22 '14 at 16:37

• increase the first space and make it symmetric: $\langle\,,\rangle$
• put \cdots in place of the arguments: $\langle\cdot,\cdot\rangle$ (this is what I prefer).
In the second one, if you don't like the space after the comma: $\langle\cdot{,}\cdot\rangle$