Tree pruning

This paper was originally written in 1965. It introduces two principles that determine the derivation of surface structure constituent trees from underlying deep structure trees. The first principle specifies that a non-branching node is eliminated, unless it is a preterminal node directly dominating a lexical item. The second principle is that if the head of a phrase is deleted, the nodes of the phrase dominating the head are eliminated. How to derive reasonable surface trees from underlying trees in a principled manner is much concern in Japanese syntax: due to the agglutinative character of the language under-lyingly complex sentences can become simple sentences at the surface level.