The third door of Anuyoga (2) (system of exposition);
exposition of a topic on the basis of the text (of a scripture), from various aspects such as, existence, non-existence, quantity or mass, space, Sparśanā, time etc..
anugamanamanngamaḥ anugamyate'nenāsminnasmāditi vā'nugamaḥ sūtrasyānukūlaḥ paricchedaḥ.
(Anu 75 HāVṛ p.27)