Bava Batra 134 - November 6, 5 Cheshvan

A story is told of one who bypassed his sons and passed his inheritance to Yonatan ben Uziel who returned a third of it to the sons. Shamai attacks him for doing it but he proves to Shamai that he was correct. Yonatan ben Uziel was considered the greatest of Hillel the Elder's students. Rabban Yochanan ben Zakai was on the opposite end of the students. And yet, he was well versed in all areas of Torah study, and more. Is one believed for inheritance and levirate (yibum) marriage to say that one has a son or a brother? On what basis? With what claims is a man believed to exempt his wife from levirate marriage? On what basis is he believed? Can a court split testimony in half and accept only part of what a person says?