overarrow and underarrow #10
Description
Command/function names you want (not necessarily adopted as a command/function name):
\overrightarrow{ math }(already implemented)\overleftarrow{ math }\overleftrightarrow{ math }\underrightarrow{ math }\underleftarrow{ math }\underleftrightarrow{ math }
Describe how you want the command/function to work.
Tensors are sometimes written in \overleftrightarrow.
Can other typesetting system (e.g. LaTeX) do the same thing? If so, provide a method to realize it.
Exactly the same as LaTeX.