What are the requirements for the prostration of forgetfulness (sujood al-sahw), and what are the prayer invalidators that are not rectified by the prostration of forgetfulness?

The jurists have agreed that the prostration of forgetfulness (sujud al-sahw) is obligatory in instances where it has been established that the Prophet, peace and blessings be upon him, performed it or commanded it. These instances are: 1. Standing up from the first tashahhud sitting. 2. Unintentionally saying the salam before completing the prayer, then returning to complete it. 3. Unintentionally adding an extra rak'ah to the prayer. 4. Doubting the number of rak'ahs, in which case one builds upon certainty and performs the prostration of forgetfulness before the salam.

In summary, the causes for the prostration of forgetfulness are addition, omission, or doubt. The prostration of forgetfulness does not compensate for abandoning a pillar, a condition, or a prayer-nullifying act.