ON FILTER CHARACTERISATIONS OF EXTENDIBILITY

Both classical and filter-theoretic characterisations of z-, C*-, and C-embedding have long been known in the literature. Localised versions of these embeddings deal with the extendibility of a single function from a subspace to the space itself and have been characterised in classical (non filter-theoretic) terms. In this paper we obtain some filter-theoretic characterisations of these localisations.