Why can't LaTeX convert this equation and display it in a PDF document?

Question

Why can't my Latex editor convert these equations below?

(x,−2x,x)+(y,−2y,y)=(x+y,−2(x+y),x+y) ∈ E
{(x,−2x,x)∣x∈R}

These are the codes I tried:

$(x,−2x,x)+(y,−2y,y)=(x+y,−2(x+y),x+y) \in E$
$ \ {(x,−2x,x) \mid x \in R \ }$

Type {...} in LaTeX needs \{...\} and the vertical line in Eq. (2) can use \mid to ensure necessary space. — Teddy van Jerry, Mar 27 '22 at 12:15
I did the {...} thingy but it still gave me errors, hold on let me update my question to update my progress. — user267208, Mar 27 '22 at 12:18
You might want to cite the specific error you get, as already mentioned number 2 should be $\{ (x,-2x,x)\mid x\in R\}$ — daleif, Mar 27 '22 at 12:30
I know why. Your minus (−) is not the standard ASCII -. And so is the vertical line. — Teddy van Jerry, Mar 27 '22 at 12:33
Despite the title, this a very similar problem to inputenc Error: Unicode char \u8: not set up for use with LaTeX — Chris H, Mar 28 '22 at 13:37

score 21 · Answer 1 · answered Mar 27 '22 at 12:44

LaTeX does not silently fail, if there is an error it is reported on the terminal and log file.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
$(x,−2x,x)+(y,−2y,y)=(x+y,−2(x+y),x+y) \in E$
\end{document}

has terminal output

LaTeX2e <2021-11-15> patch level 1
L3 programming layer <2022-02-24>
(/usr/local/texlive/2022/texmf-dist/tex/latex/base/article.cls
Document Class: article 2021/10/04 v1.4n Standard LaTeX document class
(/usr/local/texlive/2022/texmf-dist/tex/latex/base/size10.clo))
(/usr/local/texlive/2022/texmf-dist/tex/latex/amsmath/amsmath.sty
For additional information on amsmath, use the `?' option.
(/usr/local/texlive/2022/texmf-dist/tex/latex/amsmath/amstext.sty
(/usr/local/texlive/2022/texmf-dist/tex/latex/amsmath/amsgen.sty))
(/usr/local/texlive/2022/texmf-dist/tex/latex/amsmath/amsbsy.sty)
(/usr/local/texlive/2022/texmf-dist/tex/latex/amsmath/amsopn.sty))
(/home/davidc/texmf/tex/latex/l3backend/l3backend-pdftex.def)
No file cc134.aux.
! LaTeX Error: Unicode character − (U+2212)
               not set up for use with LaTeX.
See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...
l.7 $(x,−
           2x,x)+(y,−2y,y)=(x+y,−2(x+y),x+y) \in E$
?

Where the linebreak highlights the location of the error, and the message explains the problem that − is not known.

You could retype the expression with a normal ascii - character or declare the Unicode − to act like - with \DeclareUnicodeCharacter{2212}{-}

\documentclass{article}
\usepackage{amsmath}
\DeclareUnicodeCharacter{2212}{-}
\begin{document}
$(x,−2x,x)+(y,−2y,y)=(x+y,−2(x+y),x+y) \in E$
\end{document}

runs with no error and produces

score 6 · Answer 2 · answered Mar 27 '22 at 14:31

6

When we are using Unicode math then we have no problem, because your character is Unicode minus. For example in OpTeX:

\fontfam[lm]
$(x,−2x,x)+(y,−2y,y)=(x+y,−2(x+y),x+y) \in E$
\bye

gives expected result. Moreower, you can use the ∈ directly, if you know how to type it on your keyboard:

\fontfam[lm]
$(x,−2x,x)+(y,−2y,y)=(x+y,−2(x+y),x+y) ∈ E$
\bye

answered Mar 27 '22 at 14:31

wipet

74,238

1

+1 I just "borrowed" this answer here https://tex.stackexchange.com/a/638701/1090 (I trust you to be a reliable source for optex syntax:-) – David Carlisle Mar 28 '22 at 13:26

Why can't LaTeX convert this equation and display it in a PDF document?

2 Answers2