S. Carl et V. Lakshmikantham, Generalized quasilinearization for quasilinear parabolic equations with nonlinearities of DC type, J OPTIM TH, 109(1), 2001, pp. 27-50
In this paper, we consider an initial boundary-value problem for a class of
quasilinear parabolic equations whose lower-order nonlinearity is of d.c.
function type with respecxt to the dependent variable. Assuming the existen
ce of an ordered pair of weak upper and lower solutions, we establish a gen
eralized quasilinearization method for the problem under consideration. A c
haracteristic feature of this generalized quasilinearization method consist
s in the construction of monotone sequences converging to the unique soluti
on within the interval of upper and lower solutions, and whose convergence
rate is quadratic.