# Error “Unknown Unicode character” using unicode math symbols

When I use pdflatex to convert a file having unicode math symbols, it complains about that it is not found. How should I handle that? It seems to offer me a way to insert the character to a system file... and I'm unsure if that's the right thing to do.

! Package ucs Error: Unknown Unicode character 8289 = U+2061,
(ucs)                possibly declared in uni-32.def.

l.1802 $𝑍(𝑠,𝑓)=\exp⁡ (−𝑟(𝑠,𝑓)(𝑓−𝑠))=\frac{𝑍...  • please always post a small complete document that reproduces the problem, that is not the message from the standard latex unicode support so (for some reason?) you have loaded a variant from ucs package, but either way the standard \DeclareUnicodeCharacter{2061}{} will define the character to do nothing, which is what you need here (it is invisible function application marker) – David Carlisle Dec 11 '18 at 8:03 • @DavidCarlisle as the OP is presumably using utf8x, the correct syntax is \DeclareUnicodeCharacter{"2061}{} or \DeclareUnicodeCharacter{8289}{} using the decimal code point which is given in the ucs error message. – user4686 Dec 11 '18 at 13:05 • This post might help: tex.stackexchange.com/questions/464393/… – mhdella Dec 11 '18 at 21:47 ## 1 Answer You are using \usepackage[utf8x]{inputenc}, in all probability, and following the error message you can fix that this way: \documentclass{article} \usepackage[utf8x]{inputenc} \DeclareUnicodeCharacter{"2061}{}% use TeX input syntax for numbers, here hexadecimal (works only with utf8x) \begin{document} \[𝑍(𝑠,𝑓)=\exp⁡(−𝑟(𝑠,𝑓)(𝑓−𝑠))=$
\end{document}


As per uni-32.def it is found in TeXLive 2018 at /usr/local/texlive/2018/texmf-dist/tex/latex/ucs/data/uni-32.def it is a support file for ucs package. When using utf8x option to inputenc you trigger ucs (partial) usage. But it contains no definition for Unicode code point U+2061.