How can I insert the "X is a subset of Y, but is not equal to Y" symbol? I have tried using $\subsetneq$, as in $X \subsetneq Y$, but this yields the error message:

Undefined control sequence.

There is no problem using $\subseteq$.






$X \subsetneq Y$
  • 3
    Could you provide a minimal example from \documentclass to \end{document}. I think that may be amssymb is the package that provides that symbol, but there is no option to see what you actually loaded.
    – Manuel
    Jun 16, 2014 at 16:31
  • @Manuel: Added. Please see above.
    – Evan Aad
    Jun 16, 2014 at 16:39
  • 1
    A tip: You can use backticks ` to mark your inline code as I did in my edit.
    – jub0bs
    Jun 16, 2014 at 17:45

1 Answer 1


You have to load the amssymb package. Here is a possible solution:




Type ``\verb|$A \subsetneq  B$|'' to get ``$A \subsetneq B$''.

Type ``\verb|$A \subsetneqq B$|'' to get ``$A \subsetneqq B$''.




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