 We mention that we are aware that positive comprehension with the additional generalization of positive formulas allowing one to include set abstracts \(\{x \mid \phi \}\) (with \(\phi\) generalized positive) in generalized positive formulas is consistent, but turns out not to be consistent with extensionality. We are not very familiar with this theory, so have no additional comments to make about it; do notice that the translations of formulas with set abstracts in them into first order logic without abstracts are definitely not positive in our more restricted sense, and so one may expect some kind of trouble!