1) THE DEFINITION OF "TIYOMES"
OPINIONS: The Gemara teaches that when one steals a Lulav from his friend and plucks off the leaves one by one from the spine, he thereby acquires the leaves because their name has changed. Originally, they were called a "Lulav" and now they are a different object, "Hutzei" (leaves).
Rav Papa asks, if one steals a Lulav and splits the "Tiyomes," does this also represent a change in the name of the object such that the thief acquires it?
The Gemara attempts to answer Rav Papa's question from a statement of Rebbi Matun in the name of Rebbi Yehoshua ben Levi, who says that if the Tiyomes of a Lulav was removed the Lulav is invalid for the Mitzvah of Arba'as ha'Minim on Sukos. The Gemara suggests that the law is the same if the Tiyomes was not removed but only split. The Gemara refutes this suggestion and asserts that a Lulav whose Tiyomes was removed is worse than a Lulav whose Tiyomes was split, because it means that the Lulav is missing something.
The Gemara cites a second version in which Rebbi Matun says in the name of Rebbi Yehoshua ben Levi that a Tiyomes which was split is the same as a Tiyomes which was removed, and the Lulav is invalid. The Gemara concludes that the thief acquires the Lulav when he splits the Tiyomes, and it is also invalid for use on Sukos.
What exactly is a Tiyomes? The Rishonim and Acharonim discuss the definition of a Tiyomes at length. Some of their definitions are unclear, and thus there is additional discussion about what exactly they mean. Below is a summary of the KAPOS TEMARIM's understanding of the opinions of RASHI, TOSFOS, and the GE'ONIM.
(a) RASHI in Sukah (32a, DH Nechlekah) explains that a split Tiyomes refers to a split in the two middle, top leaves of the Lulav, where the spine of the Lulav ends. The split which invalidates the Lulav is a split that reaches until the leaves below. Rashi here (DH ha'Tiyomes), however, states only that the Tiyomes is the middle, top branch of the Lulav. What does Rashi here mean?
1. The Kapos Temarim in Sukah explains that Rashi understands that the middle leaf of a Lulav, determined by the highest leaf that separates from the Shidrah (spine, from which the leaves branch out) of the Lulav, is the Tiyomes. The middle leaf is comprised of two leaves that are naturally stuck together. If they are split down the middle, this is called a case of "Nechlekah ha'Tiyomes" -- "the middle leaf was split." This is also the TERUMAS HA'DESHEN's (1:96) understanding of Rashi.
2. The Kapos Temarim points out that TOSFOS (DH Nechlekah) seems to understand Rashi differently. According to Tosfos, Rashi refers to three middle leaves, each of which is comprised of two separate leaves, and which are stuck together with a red-brown peel known as the "Kora." If the Kora falls off and the middle leaf separates from the two leaves next to it on either side, the Lulav is invalid.
(b) The TESHUVAS HA'GE'ONIM and the BEHAG cited by Tosfos have a different understanding of the Tiyomes, but their definition is also subject to varying interpretations.
1. The Kapos Temarim explains that the Ge'onim essentially agree with the way Tosfos understands Rashi, that there are three middle leaves, each of which is comprised of two leaves stuck together. The difference between the Ge'onim and Rashi is that according to Rashi, the split (between the middle leaf and the two leaves at its side) is invalid only when it reaches all the way down to the Shidrah. According to the Ge'onim, the Lulav is unfit when the leaves separate even if the split does not reach the Shidrah.
2. The BEIS YOSEF (OC 645) understands the Ge'onim differently. He explains that they refer to a Lulav with two middle leaves, known as a "double Tiyomes." When there is a split between those two leaves, the Lulav is invalid.
(c) Tosfos asks that the opinion of the Ge'onim is difficult to understand, because not even one in five hundred Lulavim possess this complete type of top leaf. The Kapos Temarim explain that the reason why Tosfos writes that even one in five hundred Lulavim are not valid in such a manner is that the Ba'alei ha'Tosfos lived in France and Germany where there were no indigenous Lulavim. They imported their Lulavim from distant countries, and since the red peel falls off easily it was rare for the Lulavim to arrive with the peel. Tosfos challenges the view of the Ge'onim because it was rare for Tosfos to find a Lulav that met the specifications of the Ge'onim.
However, in Eretz Yisrael (where MAHARAM CHAVIV lived, the author of Kapos Temarim) and in Egypt, palm trees are common and it one clearly observes that most Lulavim possess the Kora. When one shakes the Lulav on Sukos, the red peel may fall off and the pairs of leaves may become separated from each other. However, the individual twin leaves remain intact, and the two halves of the leaves do not easily become separated from each other. (A similar explanation is alluded to by the Beis Yosef.)
The Kapos Temarim asserts that a Lulav which possessed the Kora originally but later it fell off is valid as long as the leaves themselves are intact. He maintains that the Ge'onim said that a split in the Tiyomes is invalid only when the Tiyomes grew without the red-brown peel and the leaves may have never been together.
(It should be noted that the most widely accepted explanation is that the Tiyomes refers to the single leaf (comprised of two thin leaves stuck together) which comes out of the highest point of the middle of the Shidrah. See REMA OC 645:3.) (D. Bloom, Y. Montrose)

96b----------------------------------------96b

2) AN OBJECT WHICH WAS CHANGED TWICE BUT REMAINED THE SAME
QUESTION: Rav Papa rules that one who steals earth from his friend and makes it into a brick does not acquire the stolen earth through the Shinuy. Since the brick can be returned to earth, the change that he made is a "Shinuy ha'Chozer li'Veriyaso" -- "a change which can return to its original state." A Shinuy which is easily reversible is not considered the type of Shinuy which makes a Kinyan. However, if one steals a brick and decomposes it into earth, that Shinuy does effect a Kinyan. Although one could remake a brick from the earth and, therefore, crumbling a brick into earth should not be considered a Shinuy which effects a Kinyan, nevertheless it is considered a Shinuy because the new brick would be a different brick altogether. It would be considered "Panim Chadashos." RASHI (DH Panim) explains that the second brick would not be the same as the first, because one could never make it exactly the same as the first brick.
Rav Papa then states another ruling. One who steals a bar of silver and forms coins out of it does not acquire the silver. The Shinuy he made is not effective because he could remake a bar of silver from the coins. However, if he steals coins and makes a bar of silver from them, his act is a valid Shinuy and he acquires the silver, because even if he would remake coins from the silver bar, they would be considered "Panim Chadashos" since the second coins are different from the first ones.
What is the Halachah in the case of one who steals a bar of silver, makes it into coins, and then remakes a bar of silver from the coins? Does he acquire the silver when he makes the coins into a bar of silver since that change is considered an effective Shinuy? Perhaps he does not acquire the silver with this act of Shinuy, since the stolen item is a bar of silver just as it was at the time it was stolen, and it is considered as though it never underwent any Shinuy. Even though it became coins in the interim stage, making coins out of a bar of silver is not considered a Shinuy. Is this case considered a Shinuy or not?
ANSWER: The KETZOS HA'CHOSHEN (360:4) answers by citing two statements of TOSFOS. Tosfos (95b, DH b'Shevach) understands that according to Rav Zevid, when one steals a non-pregnant cow and it becomes pregnant in the thief's domain, the pregnancy is not considered a Shinuy that can acquire the cow for him. It is a Shinuy ha'Chozer li'Veriyaso because when the cow gives birth it returns to its original state.
However, when one steals a pregnant cow and it gives birth, it is considered a Shinuy because it was stolen when it was pregnant and afterwards it became "empty." (The GIDULEI SHMUEL explains that the Ketzos ha'Choshen deduces this from the fact that Tosfos writes that if the profits (such as the wool) are still on the animal they belong to the owner. This implies that Tosfos understands that if an animal becomes pregnant while in the domain of the thief, no Shinuy is considered to have transpired. However, Tosfos maintains that if the profits are no longer on the animal (for example, it has given birth), the profits belong to the thief because a Shinuy has transpired.)
Moreover, the Mishnah (93b) states that when a cow becomes pregnant while in the thief's domain and then gives birth, the thief pays according to the value at the time of the theft. Tosfos (95a, DH Meshalem) states that all profits go to the thief. This is because birth is considered a Shinuy to the body of the cow, and therefore the thief acquires it through that Shinuy (see ROSH #3).
It is clear that when the thief steals an "empty" cow and at the end it is also an "empty" cow, nevertheless a Shinuy is considered to have transpired to the body of the cow as a result of being pregnant in the interim.
The Ketzos ha'Choshen applies this principle to the case of the Gemara here. He concludes that even though it was a silver bar both when it was stolen and when the thief was caught, since in between it was melted down into coins it is considered a Shinuy and the thief thereby acquires it. (See GIDULEI SHMUEL. See TABA'AS HA'CHOSHEN by ha'Ga'on Rav Chaim Pinchas Sheinberg shlit'a, and the notes on the new edition of the Ketzos ha'Choshen, who discuss this comment of the Ketzos ha'Choshen at length. See also Insights to 93b for different opinions about whether or not birth is considered a Shinuy.) (D. Bloom)