Ketuboth page 75 and 76 and Nida pages 2b and 3a

I had a few comments to add to my previous notes on Ketuboth page 75 and 76. One is that there are three different time frames. One is after the woman has gotten married. Another is when she is still in her father's home but after the engagement. A third period is when she is in her father’s home before the engagement, she gets a blemish in that second period the responsibility falls on the husband. That is to say that even though she is still in her father’s home, the fact that she is now engaged the responsibly is on the husband. Furthermore, we can push the time frame back one step at the most unless proof is brought otherwise. Therefore, if the husband finds she has a blemish after he married her, we assume it occurred either in his domain or in the fathers domain but after the engagement. Then she is the responsibility of the husband unless he can bring proof that she had the blemish before the engagement. But if the blemsih was found in the fathers domain, then we say it occurred before the engagement unless the father can bring proof that it occurred after the engagement. A further comment. I saw that Rav Shach [in laws of Sota, chapter 1, law 3] suggested that the Rambam holds both the case of the barrel and the mikve are cases of doubt. He bases that on the second suggested answer to the question from barrel to mikve in nida page 3. That is that R Shimon learns the end of tuma from the beginning, and the sages do not. However, I cannot see how the this can be derived from the second answer. And I do not see how this fits in the Gemara. After all it is R. Shimon that says the mikve is a doubt in a private domain and pure in a public domain. So when the sages disagree with him in a private domain, that means they hold it is a case of uncleanliness for a certainty. How could the Rambam decide like the case of the barrel being a doubt, and also the mikve being a doubt? That would mean he decides the law like R. Shimon in one case and like no one in the other case. For R. Shimon holds in the case of the mikve also there too it is a doubt in a private domain, but pure in a public domain. So how can the Rambam decide the case is that the mikve in the public domain is a doubt? -------------------------------------------------I had a few comments to add to my previous notes on כתובות דפים 75 and 76. One is that there are three different time frames. One is after the woman has gotten נישואין. Another is when she is still in her father's home but after the אירוסין. A third period is when she is in her father’s home before the אירוסין, she gets a blemish in that second period the responsibility falls on the husband. That is to say that even though she is still in her father’s home the fact that she is now ארוסה the responsibly if on the husband. Furthermore, we can push the time frame back one step at the most unless proof is brought otherwise. Therefore, if the husband finds she has a מום after החתונה we assume it occurred either in his domain או in the father’s domain but after the אירוסין. Then she is the responsibility of the husband unless he can bring proof that she had the blemish before the אירוסין. But if the blemish was found in the fathers domain then we say it occurred before the אירוסין unless the father can bring proof that it occurred after the אירוסין. a further comment. I saw on שבת that רב שך suggested that the רמב''ם holds both the case of the חבית and the מקוה הנמדד ונמצא חסר are cases of doubt. I think I recall that he bases that on the second suggested answer to the question from barrel to מקוה הנמדד ונמצא חסר in נידה page 3. That is that ר' שמעון learns the end of טומאה from the beginning and the חכמים do not. However, I cannot see how the this can be derived from the second answer. and I do not see how this fits in the גמרא. After all it is ר' שמעון that says the מקוה הנמדד ונמצא חסר is a doubt in a רשות היחיד and טהור in a רשות הרבים. So when the sages disagree with in a רשות היחיד that means they hold it is a case of טומאה for a ודאי. how could the רמב''ם decide like the case of the חבית being a doubt and also the מקוה הנמדד ונמצא חסר being a doubt? That would mean he decides the law like ר' שמעון in one case and like no one in the other case. For ר' שמעון holds in the case of the מקוה הנמדד ונמצא חסר also there too it is a doubt in a רשות היחיד but טהור in a רשות הרבים. so how can the רמב''ם decide the case is that the מקוה הנמדד ונמצא חסר in the רשות הרבים is a doubt?