The majority of math subscripts I am writing are not variables, but rather names (it's engineering). It is therefore appropriate to typeset them upright. My code would look much, much cleaner, if the default behaviour would be that
typesets the 'm' upright, while for the few cases where I need the normal italic font, I could use something like
To clarify: I am not looking for a macro that makes it a bit less cumbersome to typeset an index upright. I already have that. Instead, I want to change/overwrite the default behaviour (in the preamble).
Also, if you want to tell me that I should not change the default behaviour, consider me already notified.
Related questions (none of them provide the answer I am looking for):