A commentary by Govindasvamin ( a mathematician ) on the second portion is dated to c. 850 CE and attests to the scope of the work at that date ( citation ) .
The second portion presupposes the first .
A commentary by Govindasvamin ( a mathematician ) on the second portion , which presupposes the first , is dated to c. 850 CE and attests to the scope of the work at that date ( citation ) .