Query.TrimDuplicates property
SharePoint 2013
Gets or sets a Boolean value that specifies whether duplicate items should be removed from the search results. For FAST Search Server 2010 for SharePoint, this property can also be used to collapse hits in the result set.
Assembly: Microsoft.Office.Server.Search (in Microsoft.Office.Server.Search.dll)
Property value
Type: System.Booleantrue if duplicate items are removed from the search results; otherwise, false.