Prajna == 般若
There are three kinds of Prajna:
(1) Prajna of languages
(2) Prajna of contemplative illumination
(3) prajna of the characteristics of actuality
The last one is the ultimate wisdom, which is the wisdom of Buddha. Also see wisdom.
Maha-prajna-paramita-sutra == 大般若经
the Sutra was delivered by Shakyamuni in four places at sixteen assemblies. It consists of 600 volumes as translated by Hsuan-tsang. It is the fundamental philosophical work of the Mahayana Buddhism, the formulation of wisdom, which is the sixth paramita.