2. The method of claim 1 , wherein propagating the at least one knowledge value comprises iteratively applying, by the data processing system, one or more knowledge reasoners to the logical parse hierarchical representation to propagate the at least one knowledge value of at least a subset of the nodes in the logical parse hierarchical representation to one or more other nodes in the logical parse hierarchical representation based on propagation rules, wherein each application of a knowledge reasoner generates a transaction record in the transaction knowledgebase data structure identifying nodes affected by the application of the knowledge reasoner.
2. The method of claim 1 , wherein propagating the at least one knowledge value comprises iteratively applying, by the data processing system, one or more knowledge reasoners to the logical parse hierarchical representation to propagate the at least one knowledge value of at least a subset of the nodes in the logical parse hierarchical representation to one or more other nodes in the logical parse hierarchical representation based on propagation rules, wherein each application of a knowledge reasoner generates a transaction record in the transaction knowledgebase data structure identifying nodes affected by the application of the knowledge reasoner. 6. The method of claim 2 , wherein each transaction record is generated by exactly one invocation of a knowledge reasoner and stores data representing knowledge contributions from the one invocation of the knowledge reasoner.