I have 4 different constants in a given expression. Due to their physical interpretation, it makes sense to label them with non numerical indices, such as $r_+$.
The problem is that they prevent even simple commands from working, like
Solve[A (r - r_+)== B , r] (imagine the "plus sign" as an index of the second "r").
Is there any elegant way out of this? I certainly cannot name my variable $r+$ and I would like to avoid large names (since my expressions are already too large).
Thanks in advance!