A DOUBT ABOUT WHO DIED FIRST [line 1]
(Mishnah - Beis Shamai): If a house fell on Reuven and his wife, and Reuven's heirs say that she died first (so Reuven inherited all her property), and her heirs say that he died first (so they inherit her property and her Kesuvah), they divide the disputed amount;
Beis Hillel say, we leave the property in its Chazakah (this will be explained);
His heirs are Muchzak in the Kesuvah. Her father's heirs are Muchzak in the (Melug) property that she brought into the marriage and gets back (without compensation if she is widowed or divorced).
(Gemara) Question: Who is Muchzak in the property? (Beis Hillel specified who is Muchzak in the Kesuvah and Nichsei Melug, so 'the property' must refer to Tzon Barzel, i.e. property she brought into the marriage and he accepted to return its initial value if she is widowed or divorced.)
Answer #1 (R. Yochanan): His heirs are Muchzak.
Answer #2 (R. Elazar): Her heirs are Muchzak.
Answer #3 (Reish Lakish): The heirs of both divide it.
Support. (Bar Kapara - Beraisa): Since both have a claim to inherit, they divide it.
(Mishnah): If a house fell on Reuven and his mother (we do not know who died first. If she died first, he inherited her). Beis Shamai and Beis Hillel agree that his heirs divide her property with her heirs;
R. Akiva says, here also, Beis Hillel say that we leave the property in its Chazakah (this will be explained).
Ben Azai: It is bad enough that they argue in the previous Mishnah. Must you make an argument also here?!
(Gemara) Question: Who is Muchzak in her property?
Answer #1 (R. Ila): Her heirs are Muchzak.
Answer #2 (R. Zeira): His heirs are Muchzak.
When R. Zeira went to Eretz Yisrael, he retracted, and held like R. Ila.
R. Zeira: This shows that the air of Eretz Yisrael makes one wise.
Question: What is R. Ila's reason?
Answer (Abaye): The property is Muchzak in her tribe.
Answer #3 (Reish Lakish): The heirs of both divide it.
(Mishnah - Ben Azai): It is bad enough that they argue in the previous Mishnah, must you make an argument here also?!
(R. Simla'i): Since he said 'you' (and not 'Rabbeinu'), we learn from this that Ben Azai was a Talmid (who later became a) Chaver of R. Akiva.
A DIFFICULT MONETARY LAW [line 19]
(Chachamim of Eretz Yisrael): If Reuven borrowed from his father (Yakov) in Yakov's lifetime, and he died; Reuven takes from the buyers (this will be corrected and explained). This is among the most difficult monetary laws.