Parsing schemata cannot specify control strategies that guide deterministic parsers; schemata work at an abstraction level, defining a set of operations without procedural constraints on the order in which they are applied.
deterministic parsers can be viewed as optimizations of underlying nondeterministic algorithms, and we can represent the actions of the underlying parser as deduction steps, abstracting away from the deterministic implementation details, obtaining a potentially interesting nondeterministic dependency parser.