fact: Definition DuplicateFree {heading} (tup1 tup2 : @RawTuple heading) := tup1 <> tup2.
imports: Coq.Lists.List Fiat.QueryStructure.Specification.Representation.Heading Fiat.QueryStructure.Specification.Representation.Tuple Fiat.QueryStructure.Specification.Representation.QueryStructure