Rava holds that an Ed Zomem is only Pasul from the time he became an Ed Zomem
According to the first Lashon the reason is because Eidim Zomemim is a Chidush and according to the second Lashon the reason is because of the concern that a buyer used the witness to sign on his Shtar after the testimony.
If two witnesses are Mazim each one of the witnesses according to the first Lashon of Rava the Eidim Zomemim are Pasul retroactively. (1)
If two witnesses testify that Eidim are Gazlanim according to the first Lashon of Rava the Eidim are Pasul retroactively. (2)
According to the second Lashon they are only Pasul from the time they become Eidim Zomemim.
When there is a Machlokes between Rava and Abaye the Halachah is like Rava with six exceptions.
If witnesses testify that someone stole and at the same time they testified that he Shechted or sold the animal and they are Nizam they must pay four or five to the person they testified against. (3)
If witnesses testify that someone stole and Shechted or sold an animal and they were Nizam on the Geneivah the entire testimony is void because if he didn't steal he also didn't slaughter.
If they were Nizam on the Tevichah the Ganav pays Kefel and the witnesses pay two or three.
R. Yosi says that if the witnesses testified on the Geneivah and b'Toch Kedei Dibur they testified on the Tevichah when they are Nizam on the Tevichah the testimony on the Geneivah is also void and the Ganav is Patur. (4)
If someone says that this animal shall be a Temuras Olah and a Temuras Shelamim it is a Temuras Olah according to R. Meir
R. Yosi says if he intended that it should be both a Temuras Olah and a Temuras Shelamim his words are valid. (5)
R. Yosi agrees that if he said Temuras Olah first and then he had a change of heart and he said Temuras Shelamim it is a Temuras Olah.
R. Papa explains that according to R. Yosi even if he had a change of heart within Toch Kedei Dibur of She'eilas Talmid l'Rav it is a Temuras Olah.
However, R. Yosi agrees that if he has a change of heart within the Kedei Dibur of She'eilas Rav l'Talmid it is a Temuras Shelamim.
Rava says if witnesses testify that someone is Chayav Misah and they are contradicted by other witnesses and subsequently were Nizam they are put to death because contradiction is the beginning of Hazamah.
The Beraisa states if two witnesses testify that the master knocked out the eye of his servant and subsequently knocked out his tooth they must pay the value of the eye to the servant.
Rava explains the Beraisa that the first two witnesses testified that his tooth was knocked out and than his eye and the next two witnesses testified that first his eye was knocked out and than his tooth even though the second pair of witnesses is contradicted by the first they pay the value of the eye to the servant. (6)
Abaye explains the Beraisa that first two witnesses testified that his eye was knocked out and than his tooth and subsequently two witnesses were Mazim them and they said that the opposite occurred and his tooth was knocked out first and than his eye they must pay the value of the eye to the servant. (7)
A BIT MORE
1. According to the second Lashon they are only Pasul from the time they become Eidim Zomemim because of the concern that a buyer used the witness to sign on his Shtar between the time of the testimony and the time he became an Ed Zomem.
2. When witnesses testify that they are Gazlanim it is not a Chidush that the latter witnesses are believed since they are testifying on something that is unrelated to the testimony of the first witnesses.
3. However, if they testified first on he Geneivah and later on they testified on the Tevichah according o the opinion that an Ed Zomem is Pasul retroactively from the time of their testimony when they are Nizam on the Geneivah it turns out that they were Pasul from the time they testified in the Geneivah and their testimony on the Tevichah is not valid and therefore they should only have to pay Kefel not four or five.
4. R. Yosi holds that Eidim Zomemim are Pasul retroactively from the time they testified and he holds that Toch Kedei Dibur is k'Dibur and therefore the Eidus of the Geneivah and the Tevichah is regarded as one Eidus and when they became Zomemim on the Tevichah the Eidus on the Geneivah is also void.
5. It is taken out to pasture until it develops a Mum and it is redeemed and half of the money is used for an Olah and half for a Shelamim.
6. Rava holds that contradiction is the beginning of Hazamah and therefore even though the second pair of witnesses is contradicted by the first pair prior to becoming Zomemim they must pay the servant the value of the eye that they were trying to cost him.
7. Abaye holds that contradiction is not the beginning of Hazamah and once the witnesses are contradicted they no longer may becomes Zomemim.