In this sentence there are both adukkhamasukhaa which is vedanaa and
upekkhaa. What exactly is this feeling of neither-painful-nor-
pleasant? Is neutral feeling really exists or it is neutral when
there is some form of ignorance (the underlying tendency of
adukkhamasukhaa is ignorance)? Is the fourth jhaana has a neutral
vedanaa as its characteristic?
Also I am not sure if upekkhaasatipaarisuddhim should be translate
as "purification of mindfulness due to equanimity", or "purification
of mindfulness and equanimity", or maybe purification through
mindfulness and equanimity".