Hetucakra
Hetucakra or Wheel of Reasons is a Sanskrit text on logic written by Dignaga (c 480–540 CE). It concerns the application of his 'three modes’ (trairūpya), conditions or aspects of the middle term called hetu ("reason" for a conclusion) or linga ("mark", "sign" of a sound argument) in a valid inference within the Indian logico-epistemic tradition, sometimes referred to as Buddhist logic.