Parity Preference of the Universe

Determine whether the universe exhibits a distinct preference for parity across astrophysical properties, specifically whether such properties are more likely to be classified as even or odd.

Background

The paper investigates whether the universe shows a parity preference by analyzing the number of member galaxies in galaxy groups and clusters using the DESI Legacy Imaging Surveys DR9 group catalog. The authors motivate their study by noting that, beyond known asymmetries such as spiral galaxy spin chirality, it remains unclear whether the universe prefers even or odd classifications in general.

While the paper presents evidence that the number of galaxies per group tends to be odd, the quoted uncertainty in the abstract concerns a broader question: whether the universe has a distinct parity preference across astrophysical properties writ large, not limited to group membership counts.