Missing or unrecognized delimiter for \left

[xpqiu]

Missing or unrecognized delimiter for \left .

For example,
$$
\phi_2(x,y)=\left{
\begin{array}{11}
1 & \textrm{if x contains 'stock' and y is 'sport'}\
0 & \textrm{otherwise}
\end{array}
\right..
$$

[admnll]

Remove the first bracket and replace it with \ lbrace
$$
\phi_2(x,y)=\left\lbrace
\begin{array}{ll}
1 & \textrm{if x contains 'stock'
and y is 'sport'} \newline
0 & \textrm{otherwise}
\end{array}
\right.
$$

[muzimuzhi]

According to GitHub Flavored Markdown Spec, Sec. 6.1

Any ASCII punctuation character may be backslash-escaped:
\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\@\[\\\]\^\_\`\{\|\}\~

Hence the whole process is

• you type in \left\{ and gfm parser uses it as input
• gfm parser returns \left{ and github-mathjax (and mathjax) uses it as input
• mathjax complains about { is not a delimiter

And, duplicate of #26 .

[muzimuzhi]

Sorry, I have not found that this is a so-old issue.

[piglaker]

thx