I need to write in a caption $\overleftarrow{A}$ and make it bold, but when I compile I get the error

"illegal parameter number in definition of \reserved@a."

So to make it compile I use $\protect\overleftarrow{A}$, but if I try using \bm to make the all part bold I get the same error reported above. Any help please?

1 Answer 1


With \boldmath:




\caption{text \boldmath$\protect\overleftarrow{A}$ }


enter image description here

  • using \boldmath the difference between bold e normal is almost unnoticeable in my text. Is there a reason why?
    – user160430
    Commented Jul 20, 2018 at 9:46
  • actually to be precise using \boldmath$\protect\overleftarrow{A}$ in my caption does not produce a symbol in bold but it compiles. Please help.
    – user160430
    Commented Jul 20, 2018 at 15:53
  • @user160430 How do you compile? With pdflatex or something else? Do you get any errors or warning in your log? Commented Jul 20, 2018 at 15:54
  • I compile with pdftexify and yes I receive some warnings.
    – user160430
    Commented Jul 20, 2018 at 18:55
  • @user160430 Can you share the .log file? Commented Jul 20, 2018 at 19:05

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .