What is the ruling on someone who swore to study a specific part, but did not complete it due to being overcome by sleep? Is fasting required of him?

If you utter an oath, expiation becomes binding upon you if you do not fulfill what you swore to, unless sleep overtakes you and you are unable to perform the action, in which case you are considered to be in the position of one coerced, and no expiation is binding upon you. However, if you were able to perform the action but neglected it until you slept, then expiation is due for each oath. It is preferable to offer expiation in all cases. The expiation for an oath is feeding ten poor persons, or clothing them, or emancipating a slave. If you are unable to do that, then it is fasting for three consecutive days. It is advised not to make many oaths.