@maripat Great catch! Yes, we’ll definitely want to define this. For consistency of formatting, it’ll be ideal to use mathjax for “n = c/v” and clarify the phrasing that indicates that c is speed of light and v is velocity of light through the medium
Since editing suggestions to include mathjax is a bit difficult, I’ve submitted a separate suggestion to address the above. I will close this suggestion for now but let me know if you have any other concerns!