[982] Which phenomena (dhammā) belong to the formless sphere (arūpāvacara)? The four formless states (āruppa), as wholesome, as resultant, and as functional — these phenomena belong to the formless sphere.
Which phenomena do not belong to the formless sphere? Those belonging to the sense sphere (kāmāvacara), those belonging to the form sphere (rūpāvacara), and the unincluded (apariyāpanna) — these phenomena do not belong to the formless sphere.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.