Study Guide Shabbat 3 Today's shiur is sponsored by Eva Schweber and Rabbi Daniel Schweber in memory of their father, Ken Schweber, Yaakov Kapel ben Moshe and Rivka, z"l.  The mishna says there are eight cases - but there seem to be twelve or sixteen, depending on how you count. Which were the eight that the mishna meant - why were only those counted? Shmuel says that whenever the rabbis say exempt (patur) regarding Shabbat issues and it means exempt by the Torah but prohibited by the rabbis, other than three cases. Are there other exceptions? Why if two people do a melacha together, are they each exempt from bringing a sin offering? Abaye asks if when one's hand is in the airspace of another domain while carrying something, is one's hand considered in a karmelit and one would be forbidden by rabbinic law to return one's hand to the original domain? Two contradictory braitot are brought to suggest that perhaps the tannaim debated exactly this issue - however several other possibilities are brought - all of which would not be able to be used to answer the question.