What are the requirements for sajda sahw? موجبات سجود السهو

Praise be to Allah, and may Allah’s peace and blessings be upon the Messenger of Allah, his family and his companions.
As to what follows:
With regards to answering your question we say, success is by Allah Almighty.
Sajdah sahw requires one of three things:
1.    addition
2.    deficiency
3.    doubt
If the sahw (inattention) is due to increasing something then sajdah should be performed after taslim. If sahw is due to deficiency then sajdah should be performed before taslim. As for doubting the ruling is as follows: If a person basis his doubt on conviction then sajdah should be performed before taslim, but if he basis his doubt on uncertainty then sajdah should be performed after taslim. This is the more correct of opinions held by scholars with respect to sujud.
And Allah knows best.

Your brother,
Dr. Khalid al-Muslih
23 / 03 / 1429 AH