StardogUpdateGraph.cs

// Assumes we already have a StardogConnector in the variable stardog

// Create the Triples we want to remove
NodeFactory factory = new NodeFactory();
List<Triple> toRemove = new List<Triple>();
toRemove.Add(new Triple(factory.CreateUriNode(new Uri("http://subject")), 
                        factory.createUriNode(new Uri("http://predicate")), 
                        factory.CreateUriNode(new Uri("http://object"))
            );
// And so forth...

// Now go ahead and remove from our target graph
// Since we don't have any additions we can provide null for that argument
stardog.UpdateGraph(new Uri("http://graph"), null, toRemove);