code class$=$"asciimath"$>$Q$1$L$\_(1)=\{2^($n$)1^($m$)3^($k$)$:n$,$m$,$k$>=0\}$ on $\backslash$sum $=\{1,2,3\}.$ L$\_(2)=\{($w$\{$a$,$b$,$c$\}^(*))$:$\}$ : every appearance of a in w before every appearance of c in w