Using single brackets () versus doublebrackets ([]) is a personal preference and really depends on how you've been taught commands and shell scripting.
A stereotype allows you to attach a new meaning to a UMl foundation class, such as class, and it is represented on a UMl diagram as a name surrounded by doublebrackets .
However, a slash or a double slash ( / or // ) at the front of a predicate in square brackets does not have a context and therefore refers to the root of the document.