A Particle is the lexical core of an uninflectable function word in Zwicky's sense: its form, its
position relative to its host, and its Clause.Distribution over sentence types in embedding
contexts. The distribution records where the source finds the particle obligatory, optional or
excluded, and nothing where the source is silent; it records distributional felicity, not the
licensing mechanism, which is a study's matter. The cells where a particle is licensed are
p.distribution.possible, and its sentence-type and embedding-context profiles are that
relation's dom and cod.