When I use the copyright symbol $\copyright$ the messages:

Missing character: There is no © in font txr!
Missing character: There is no © in font txr!
Missing character: There is no © in font txr!
Missing character: There is no © in font txr!


these are displayed in the log file and the symbol is not displayed (why the message is printed four times instead of one)? is there another way to print this symbol? thanks a lot

• Welcome to TeX.SX! Please help us help you and add a minimal working example (MWE) that illustrates your problem. Reproducing the problem and finding out what the issue is will be much easier when we see compilable code, starting with \documentclass{...} and ending with \end{document} – Saravanan Nov 20 '17 at 15:41
• Did you load the font with T1 encoding? – Bernard Nov 20 '17 at 15:47
• Please, look this answer: tex.stackexchange.com/a/1677/69174 – Giacomo Alessandroni Nov 20 '17 at 15:52
• do you really want copyright in math mode? – David Carlisle Nov 20 '17 at 16:12
• no, i just want to display the symbol and i thought that it is used in math mode ... this is wrong? – Athanasios Margaris Nov 20 '17 at 17:10

The copyright and other textcomp package symbols are not usable in math mode.
\textsuperscript{\textcopyright}