Аннотация
In this work the sufficient conditions of well-posedness in L2 (−∞, +∞) of the differential equation −y‴+p(x)y′+q(x)y=f(x) with smooth, unbounded and fast oscillating coefficients are received. We give the maximal regularity estimate ‖ y‴‖2+‖ py′ ‖2+‖ qy ‖2≤C‖ f ‖2 for the solution y where ‖ ⋅ ‖2 is a norm in L2 (−∞, +∞). Here, the intermediate coefficient p is not controlled by q and |q| is an unbounded function. Conditions obtained by us are close to necessary.