Effect of a saturated-lipid cross-linker with p = 5 on the phase boundaries of the system below the temperature of transition to the gel phase of the pure, saturated lipid system. Again, dotted lines show the phase boundaries without cross-linkers, while solid lines show the boundaries for a concentration z = 0.03 of cross-linkers. The values of the parameters are (see (19)) Jss = 1.0, k1 = 1.0, Jus = 1.8, Jcs = 2.4, k2 = 0.21, k3 = −0.25, J′us = 0.7, and J′cs = 0.0.