We introduce the concepts of the Fourier transform and convolution generated
by an arbitrary restriction of the differentiation operator in the space
L2(0,b). In contrast to the classical convolution, the introduced
convolution explicitly depends on the boundary condition that defines the
domain of the operator L. The convolution is closely connected to the inverse
operator or to the resolvent. So, we first find a representation for the
resolvent, and then introduce the required convolution.Comment: 15 page