Some Equivalence Transformations for L’Algebra

• Commutativity:

  • union(A,B) = union(B,A) (within single document)
  • but d-join is not commutative

• Associativity:

  • union, intersect, d-join

• Idempotence:

  • union(A,A) = A

• Distributivity:

  • //book/(title | author) = //book/title | //book/author

• Neutral Elements:

  • union: {}
  • d-join: $root(?)

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