Yevamot 92a and Yevamot 92b, the difference between a ruling of a court and a mistake, and their ramifications, and then what happens with mistakes in yibum (a woman thinking she does or does not need yibum).
Yevamot 92a and Yevamot 92b, the difference between a ruling of a court and a mistake, and their ramifications, and then what happens with mistakes in yibum (a woman thinking she does or does not need yibum).