Upper and lower solutions method for a class of singular fractional boundary value problems with -Laplacian operator.
Variational oscillation criteria for nonlinear nonhomogeneous differential equations.
Zeros of derivatives of solutions to singular conjugate BVPs
Positive solutions of the singular conjugate BVP are studied. The set of all zeros of their derivatives up to order is described. By means of this, estimates from below of the solutions and the absolute values of their derivatives up to order on the considered interval are reached. Such estimates are necessary for the application of the general existence principle to the BVP under consideration.
Сингулярно возмущенные краевые задачи при наличии нулевых точек спектра предельного оператора.