Rabbi Joshua said until the one reproved curses the reprove. Rabbi Johanan said that one should reprove only until the one reproved "rebukes" the reprover. Rav said that one should reprove until the one reproved strikes the reprover. Samuel said that one should reprove until the one reproved "curses" the reprover. He was known never to reprove anyone sharply but always with charity and gentleness. They reprove the Husband and urge his reform. Kac character formula for them to reprove the Macdonald identities. Rabbi Eleazar ben Azariah wondered whether anyone in his generation knew how to "reprove". The Gemara discussed how far one should reprove another. Separately, a 1927 paper of Solomon Lefschetz used topological methods to reprove theorems of Riemann.