Since each derivation is defined by three fixed indices (the g-span) and one free index (the split point), the complexity of the algorithm is O(n 4 ) time and O(n 3 ) space.
recent work in dependency parsing has been restricted to applications of secondorder parsers, the most powerful of which (Carreras, 2007) requires O(n 4 ) time and O(n 3 ) space, while being limited to second-order parts.