The head of my document looks like





\articletype{Regular article}

But when I try to compile the document, it fails and writes:

Package inputenc Error: Keyboard character used is undefined(inputenc) in inputencoding utf8. \section.

The error appears for the string \section{Derivation}, but I don't understand, what is the reason for this.

Can you help?

  • 5
    inputenc defines definitions for a few hundred characters and Unicode has a few thousand characters so getting this error is expected. If you had shown the full error, or shown a test document, we would know which character was undefined, and could suggest a definition. – David Carlisle Jul 19 '17 at 6:51