In Jainism, time is divided into vast cycles called Ara (also spelled as "Aara" or "Kalachakra"). Each Ara is a large epoch, and there are six Aras in each half of the time cycle (Utsarpini - ascending, and Avasarpini - descending).

The term "prahar" is a unit of time, traditionally used in Indian timekeeping, and refers to a period of approximately 3 hours (one day consists of 8 prahars).

When referring to 3 prahar, it usually means a duration of about 9 hours.

However, if your question is about which Ara is associated with the concept of "3 prahar" in Jain cosmology, it is likely referring to the fifth Ara (Pancham Aara) of the Avasarpini (descending) time cycle.

Details:

• In the fifth Ara (Pancham Aara), it is said that the maximum human lifespan is 3 prahar, which translates to about 9 hours. As time progresses in this Ara, human lifespan, height, and moral values diminish. Ultimately, at the end of the fifth Ara, the lifespan reduces to as little as 3 prahar (9 hours).

Summary: 3 prahar (9 hours lifespan) is associated with the end of the fifth Ara (Pancham Aara) in Jain cosmology.