My strong preference is to use $\C$ to denote the set of complex numbers, just as I use $\R$ to denote the real numbers — whether with \mathbb or \mathbf.

Several other packages use their own definitions of \C: t2aenc.def (called from \usepackage[T2A,T1]{fontenc}); mismath.sty; and either hyperref.sty or some package it calls.

My workaround for this shown in the MWE below.

Question: Is there a simpler method to accomplish this — without repeatedly redefining \C?


  • It is very unlikely I'll ever need the \C from babel's use of T2A. I'm unsure of how hyperref uses \C. (It's for a double-grave accent in Serbo-Croatian and Slovenian.)
  • I am using pdflatex and not xelatex or lualatex!

Source MWE:


% Avoid \lll clash with def in amssymb.sty:
    \let\lll\relax \let\LLL\relax % undefine them

% Choose ONE of the following two defs:

% First 
    \ifcsname C\endcsname

\usepackage{mismath} % defines \Z, \Z, \Q, \R, \C with mathbf

\@ifpackageloaded{hyperref}{% then



$\N \subset \Z \subset \Q \subset \R \subset \C$


Related post: Possible to use$ \C$ for complex numbers with T2A encoding?

  • 1
    If you want your definition to win do as late as possible \AtBeginDocument{\def\C{\numsys{C}}}. – Ulrike Fischer Aug 5 '19 at 21:00
  • I do want mine to win, and this works! Please make as an answer. (Do you happen to know how/where the \C is used by hypreref, just in case I'm overlooking something I might actually need there?) – murray Aug 5 '19 at 21:07
  • hyperref adds a definition for the accent command for the bookmarks. if you don't need the command in this sense, it shouldn't matter. – Ulrike Fischer Aug 5 '19 at 21:13

If you want your definition to win add as late as possible


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