Figure 1

Phase plots for the VOFVDPM with \(\pmb{q_{1}(t)=q_{2}(t)=1-1t/3{,}000}\) and \(\pmb{q_{1}(t)=q_{2}(t)= 0.9+1t/ 3{,}000}\) (the other common parameters are \(\pmb{a=0}\) , \(\pmb{\mu =2.5}\) ) [blue line: \(\pmb{(x(0),y(0))=(0.2,0.3)}\) ; red line: \(\pmb{(x(0),y(0))=(0, 4)}\) ].