  For a linear ODE with indeterminate coefficients, we explicitly exhibit a
fundamental system of solutions, in terms of the coefficients. We show that the
generalized Wronskians of the fundamental system are given by an action of the
Schur functions on the usual Wronskian, and thence enjoy Pieri's and
Giambelli's formulae. As an outcome, we obtain a natural isomorphism between
the free module generated by the generalized Wronskians and the singular
homology module of the Grassmannian.
