How can I find the list of all valid expression format for SNAP band math operation?

How can I find the list of all valid expression format and list of all function in SNAP band math operation?

You can find it in the Help.
Look for Band Maths Expression Editor.

Hi, this would be a very useful link, however with SNAP 6.0 i do not have such link under the help tab, please can you be more specific as to how to access this documentation. Thanks very much

In the Band Maths module, when you click on Edit Expression, you have another window popping with also a help button.