1. A method for resolving conflicting graph mutations implemented by a computer comprising at least one processor, the method comprising: storing, in a worker system of a distributed computing system, graph data for at least a partition of a graph representing relationships among a set of tangible items that model a real-world condition having an associated problem, the distributed computing system operating in synchronized steps under control of a master system; receiving a plurality of conflicting mutation requests to mutate the graph during a first step of the synchronized steps, the conflicting mutation requests including respective values for a graph component; resolving a conflict between the respective values of the conflicting mutation requests during a second step of the synchronized steps that follows the first step, the conflict resolved with a conflict resolution function that lacks direct access to the graph data; and updating the graph data responsive to a result generated by resolving the conflict using the conflict resolution function.