We can extend the NotPushdown rewrite to handle more cases, which can result in better bounds, or at least simpler expressions to evaluate.

For example (pseudocode):

• Not (ComposeA p1 p2) -> ComposeM (Not p1) (Not p2)
  • Should help $nor queries, or more complex boolean expressions.
• Not (Default e) -> Default (Not e)
  • In an EvalFilter context, Default returns either its argument or the negation of its argument.
  • This will help us combine $not with $exists.
• Not (Constant e) -> Constant (Not e)
  • Should help with constant folding.