So sets of links between facts and their sources can be modeled on a graph as relationships. So provenence in a context store containing facts is a knowledge graph. We have three in this example we have three source data in graffiti that turned episodes. We have two entities extracted from the episodes patient and penicellin and an edge between them. This graph triple the two entities and the edge can be hydrated as a fact. Patient has a penicellin allergy. Tracing a fact to its source is just a graph walk. So it's pretty simple and easy to map source to fact on the first right but keeping it correct while the graph changes can be really hard when new data uh so for example when two entities merge the merged entity needs to keep all source links from both otherwise we silently drop a source and we lose lineage. And when new data contradicts existing data, mutating it, we need to capture this lineage too. In the rightmost card, a fact is rendered invalid by new data. And in graffiti, an invalid date is added to the mutated edge. And the source episodes that resulted in the edge mutating are noted against the fact.