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