Poset embeddings of Hilbert functions

For a standard graded algebra , we consider embeddings of the poset of Hilbert functions of -ideals into the poset of -ideals, as a way of classification of Hilbert functions. There are examples of rings for which such embeddings do not exist. We describe how the embedding can be lifted to certain ring extensions, which is then used in the case of polarization and distraction. A version of a theorem of Clements-Lindstrom is proved. We exhibit a condition on the embedding that ensures that the classification of Hilbert functions is obtained with images of lexicographic segment ideals.