Been trying to figure it out for an hour myself and another hour looking around, I cannot find anything with the $c^{mn}$ part.

$$L=\{a^mb^nc^{mn}\mid m>n\}$$

  • $\begingroup$ What have you tried? Where did you get stuck? We do not want to just hand you the solution; we want you to gain understanding. However, as it is we do not know what your underlying problem is, so we can not begin to help. See here for tips on asking questions about exercise problems. If you are uncertain how to improve your question, why not ask around in Computer Science Chat? $\endgroup$
    – Raphael
    Nov 24 '18 at 11:06