The subject of Prof. Titchmarsh's book is the expansion of an arbitrary function in terms of the eigenfunctions of linear differential equations; to be precise, in terms of functions which satisfy ...

Figure 9. Mean function and eigenfunctions for longitudinal behavioral data. The estimated mean function μ^ and the first three estimated spherical eigenfunctions ϕ^1, ϕ^2, ϕ^3 for the ...