In the paper, efficient conditions are found guaranteeing that every solution to the problem u'(t) ≥ ι(u)(t), u(a) ≥ h(u) is nonpositive, where ι : C([a, b]; R) → L([a, b]; R) and h : C([a, b]; R) → R are linear bounded ...

Nonimprovable sufficient conditions are established for unique solvability of the boundary-value problem u`(t) = l(u)(t) + q(t), u(a) = λu(b) + c, as well as for nonnegativeness of its solution, where l : C([a, b]; R) → ...