# LaTeX symbol for c_0

Given the importance of the speed of light to so many in areas of science, engineering, computing, etc. and so many areas of daily life, particularly for example with the electromagnetic spectrum that continues to skyrocket in value, I have been unable to find a specific LaTeX symbol for the "invariant speed" of relativity theory, often represented by an italic c followed a subscript 0. From a LaTeX perspective, the closest code I've found to represent what is often coded as \textit{c}_0 is:

\newrobustcmd{\clight}{$c_{\scalebox{.8}{${\text{\tiny 0}}$}}$}


but the above code is problematic when imbedded in other LaTeX math functions, which has led me to post this question. What am I missing?

\end{document}

• Depends on how much effort you want to put in can make mathchoice too. Jan 20 at 8:16
• @DavidCarlisle -- thanks for the edit! (I had forgotten that \ensuremath has been part of the LaTeX format for a while.)
– Mico
Jan 20 at 8:16
• @user202729 -- I'll let the OP speak up on wheher he/she foresees use cases of \clight while in scriptstyle or scriptscriptstyle mode...
– Mico
Jan 20 at 8:18
• "for a while" yes, since 1994 :-) Jan 20 at 8:18
• @user202729 actually use of this as in in subscripts is Ok as is, it doesn't get smaller but then neither does the 2 in x^{x^2}} the fact that nothing gets smaller than scriptscriptstyle is by design, so we have a chance to read it in paper without zoom facilities Jan 20 at 8:20