Is it really true that every time Rabbi Yehuda says "when is this the case?" in the mishna, he is explaining the rabbi's opinion and not disagreeing? In Sanhedrin when it talks about gamblers and others who are not allowed to testify in court, Rabib Yehuda said "When is it the case? Only when they have no other occupation." And it seems that the rabbis disagree from another source. The gemara proves that the opinion from the other source isn't the rabbis' but Rabbi Tarfon's. How can one do an eruv to include others who may want to join. By what point do they need to decide when they want to join - before Shabbat or during? Does it have to do with the laws regarding breira, retroactive designation? Is a child automatically included in their mother's eruv? Until what age? There seem to be some contradictions between sources and the gemara tries to resolve them. Can a man make a eruv for his wife, for his children or Jewish or Canaanite slaves without their knowledge? What if they protest? Two meals' worth are required for an eruv techimum. A Shabbat size meal or a weekday? Which is larger - there is a debate about this!! What is the size of an average loaf and is the size of tat loaf, the measure for two meals or only part of the average loaf? Rabbi Yochanan ben Broka and Rabbi Shimon disagree about these two points.