public void SelectRelationships( 
   IReadOnlyCollection<string> relationships
)

{
  // get the active investigation view
  var iv = KnowledgeGraphInvestigationView.Active;

  // clear any TOC selection
  iv.ClearTOCSelection();

  // select entities
  List<string> entities = new List<string>();
  entities.Add("Person");
  entities.Add("Org");
  iv.SelectEntities(entities);

  // or select relationships
  List<string> relationships = new List<string>();
  relationships.Add("HasEmployee");
  iv.SelectRelationships(relationships);

  // or select a combination
  List<string> namedObjectTypes = new List<string>();
  namedObjectTypes.Add("Person");
  namedObjectTypes.Add("Org");
  namedObjectTypes.Add("HasEmployee");
  iv.SelectNamedObjectTypes(namedObjectTypes);
}