Standard transmutation operators for the one dimensional Schrödinger operator with a locally integrable potential

We study a special class of operators T satisfying the transmutation relation(d2dx2−q)Tu=Td2dx2u in the sense of distributions, where q is a locally integrable function, and u belongs to a suitable space of distributions depending on the smoothness properties of q. A method which allows one to construct a fundamental set of transmutation operators of this class in terms of a single particular transmutation operator is presented. Moreover, following [27], we show that a particular transmutation operator can be represented as a Volterra integral operator of the second kind. We study the boundedness and invertibility properties of the transmutation operators, and use these to obtain a representation for the general distributional solution of the equation d2udx2−qu=λu, λ∈C, in terms of the general solution of the same equation with λ=0.