infinite space, infinite consciousness, vacuity, peak of existence
The formless realm has four divisions, in ascending subtlety:
| # | Name | Sanskrit | Tibetan | Object of absorption |
|---|---|---|---|---|
| 1 | Sphere of Infinite Space | Ākāśānantyāyatana | ནམ་མཁའ་མཐའ་ཡས་ | Limitless space |
| 2 | Sphere of Infinite Consciousness | Vijñānānantyāyatana | རྣམ་ཤེས་མཐའ་ཡས་ | Limitless consciousness |
| 3 | Sphere of Vacuity (Nothingness) | Ākiñcanyāyatana | ཅི་ཡང་མེད་ | “There is nothing” |
| 4 | Sphere of Neither Perception nor Non-Perception (Peak of Existence) | Naivasaṃjñānāsaṃjñāyatana / Bhavāgra | སྲིད་རྩེ | Subtlest possible cognition |
The fourth — Bhavāgra, “peak of existence” (སྲིད་རྩེ་, srid rtse) — is the highest possible rebirth in saṃsāra.
Source: class_20_wheel-of-life-part-13-of-13.md confirms four divisions; specific names are deferred to the Master’s Course and supplied here from standard Abhidharma sources.