I was looking for a reference in ADO.NET Entity Framework documentation (via Google) if a Complex type in an EDM could be part of an association (relationship) like Hibernate supports. I needed this for some tool I'm working on . Google gave me an interesting link, namely to a patent held by MS about relationshipsets in the EDM. It refers to other patents of similar straight-forward concepts, either based on stuff defined by Codd or defined by other O/R mapper frameworks like Hibernate or Toplink long before the filing took place. Why these common concepts are even patentable (as they're discoveries in math-space, so not really inventions) is beyond me.
With almost bleeding ears I'm currently listening to show #369 of .NET Rocks!, which has Danny Simmons and Stephen Forte as guests. Danny is of course known of his major role in the Entity Framework (EF) design and Forte is one of the Council of Wise Men (TM) which are advising the EF team how to make the EF a better product / system / whatever.