  In this note we describe a space-time boundary element discretization of the
heat equation and an efficient and robust preconditioning strategy which is
based on the use of boundary integral operators of opposite orders, but which
requires a suitable stability condition for the boundary element spaces used
for the discretization. We demonstrate the method for the simple spatially
one-dimensional case. However, the presented results, particularly the
stability analysis of the boundary element spaces, can be used to extend the
method to the two- and three-dimensional problem.
