Nested Coordination in Universal Dependencies

One principled problem with the UD approach to coordination known to the Universal Dependencies (UD; http://universaldependencies.org/; Nivre et al., 2016) community concerns nested – i.e. immediately embedded – coordination, as in:1 (1) Tom and Jerry and Scooby-Doo There are three possible ways to structure (1): (2) Tom and Jerry and Scooby-Doo (3) [Tom and Jerry] and Scooby-Doo (4) Tom and [Jerry and Scooby-Doo] That is, (1) may be construed as flat ternary coordination (cf. (2)), or as binary coordination whose first (cf. (3)) or second (cf. (4)) conjunct is itself a coordinate structure. UD is not able to distinguish the first two structures, (2)–(3) – it assigns the same representation (5) to both, while representing (4) as (6):