1. A Pirtza on the side of a Movoy can be up to 10 amos. Does that wall with the pirtza need to have omed meruba mi'parutz?
2. I understand that a chazer mfulash just needs a pas at both sides(?).If I am right doesn't this chatzer just have two full walls(the other 2 are parutz mruba)?
3. Also, is there anyplace in Jerusalem that is considered a R. Harabim. If not, why not
A. Fine, Jerusalem
1. The Shulchan Aruch (OC 363:2) writes that if a Chatzer is Parutz "b'Milu'o" up to 10 Amos, the way to permit it is to set up a Pas of 4 Tefachim. The Mishneh Berurah (#5) writes that "b'Milu'o" means that the entire wall is Parutz. We learn from this that the wall with the Pirtzah does not require Omed Merubeh Al ha'Parutz. However, the other 3 walls must remain Omed Merubeh. (See Chazon Ish 65:33.)
2. The Mishneh Berurah (364:4) writes that even if the Chatzer is Mefulash on both sides to Reshus ha'Rabim, it is sufficient to put Pasim on both sides, as you understood. However, it seems that the Chazon Ish (ibid.) is concerned with what is worrying you about this, and he writes that this matter requires much further study because a Chatzer always requires 3 complete walls of Omed Merubeh Al ha'Parutz. Otherwise, it is considered a Karmelis.
3. According to the first opinion in the Shulchan Aruch (OC 345:7), any street which is 16 Amos wide is considered Reshus ha'Rabim. (Of course, there are many opinions in the Halachah on this matter, and I am mentioning only one opinion for the moment.)
Thanks for answering. I already forgot the questions, but now you made me do a little chazara.
About answer one, it seems to me that you are saying since the gemarah is talking about a mavoy (which means the entrance is open, parutz murabah), so the other side with the pirtza has to be omed mruba. Am I correct?
This is correct, as stated by the Mishnah Berurah in Bi'ur Halachah 362:8, DH Parutz, that the prohibition concerning Parutz Merubeh applies to the first 3 walls, while concerning the 4th wall, even if totally Parutz, it is sufficient to make a slight Tikun.
So, in your case, the side opposite the 4th Parutz side must be Omed Merubeh.
Yasher Ko'ach for your very alert comments.