Sanghabhuti, an Indian Buddhist monk, who travelled to China at the end of the fourth century AD, was the author of a commentary on :

States that Indian Buddhist teachers travelled to faraway places carrying texts which were translated in East Asia.

A student could use this rule to ask whether a travelling Indian monk like Sanghabhuti might have carried or produced commentarial texts (e.g., on the Prajnaparamita) that were then translated in China.

Gives the concrete example of Faxian (early 5th c.) who collected manuscripts in India and took them back to China.

Compare dates/routes: if Sanghabhuti was active around end-4th c., a student could check whether similar pilgrim activity (collecting/commenting texts) occurred slightly earlier and thus was plausible.

Notes Xuanzang’s practice of bringing Sanskrit manuscripts back to China and translating them—showing a pattern of textual transmission between India and China.

Use this pattern to investigate whether commentaries authored in India were known in Chinese catalogues or translation histories (search Chinese bibliographies for Sanghabhuti or Prajnaparamita commentaries).

Mentions the Karakoram/central Asian routes used by Buddhist monks travelling to China, establishing plausible physical routes for textual transmission.

A student could map Sanghabhuti’s proposed travel date against known use of these routes to assess logistical plausibility of him carrying a commentary to China.

Describes the broad spread of Buddhism from India through Central Asia to China and that Buddhist teachings were reconstructed from translated/edited texts.

This suggests checking whether the Prajnaparamita and its commentaries were among works transmitted along these channels and whether author attributions appear in surviving Chinese or Tibetan editions.