[51] For whomever mind (citta) is arising, has that one's mind arisen?
Yes.
Or else, for whomever mind has arisen, is that one's mind arising?
At the moment of the dissolution (bhaṅgakkhaṇa) of mind, the mind of those persons has arisen, but their mind is not arising; at the moment of the arising (uppādakkhaṇa) of mind, the mind of those persons both has arisen and is arising.
For whomever mind is not arising, has that one's mind not arisen?
At the moment of the dissolution of mind, the mind of those persons is not arising, but it is not the case that their mind has not arisen. For those who have attained cessation (nirodhasamāpanna) and for non-percipient beings (asaññasatta), their mind is neither arising nor arisen.
Or else, for whomever mind has not arisen, is that one's mind not arising?
Yes.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.