$begin{eqnarray}
    dot{x}&=&f(x,mu)\
    dot mu_i&=&left{begin{matrix}
    	g_{i}(x) ;;;;;;if; mu_{i}>0 ;;, \
    	text{max}(0,g_{i}(x));; text{if} ;mu_{i}=0.
    end{matrix} right.
end{eqnarray}$