I ask this under the assumption that "M-F" and "M~F" are the most commonly preferred notations for abbreviation weekday schedules if using 3-letter abbreviations like "Mon" and "Fri" take up too much space.
Alternatives that I can think of include:
MTWTF
and
MTWRF
I wonder what is most commonly used, the hyphen or tilde. It's difficult to perform a Google search to count the number of results because it doesn't seem like Google Search can search up punctuation marks.