I heard before (I think in the name of the Rogatchover) that there is one Amora in every masechta of Talmud that does not appear in any other masechta. Is there a source for this, and is there a list ...
What are the teachings labeled "Tana Dvei Rabbi Ishmael"? Are they Braisos or Amoraic teachings? On one hand, on Shabbos 26b we find it arguing on Rabbi Shimon ben Elazar (a Tana). On the other ...
I had always assumed that R' Yehoshua Ben Levi was an Amorah. However, we know he is quoted in the mishnah in Avos (Perek 6 Mishnah 2. Which is really a braisa, not a mishnah, but still a Tannaic ...