bor is reshut hayachid. can get water from bor climb down. behemot cannot. had to climb down, bring up for behemot. made bor on side of highway.
made pasi beraot. make mechitza around bor, take away from highway!
even though nifratz in the middle. each an amah by an amah, and many many amot missing in the middle.
normally we would not accept because parutz meruba al haomed, midirabbanan. but since for purpose of olei regalim, we are meikil.

tanaim have machloket where these pasim located. not in mid-highway. on side of highway, if traffic goes through and thru. do we say asa rabim umevatlei mechitza. machloket rabbi yehuda and rabanan.

truth is, says gemara, both agree that it does cancel. only argue when cancel. if sturdy mechitza, does not bother me. when mechitza gruah, is machlokety

one says if have all 4 sides. others say, if missing too much.

Then, Tosafot has a little innocent question. both agree to asi rabim umevatlei mechitza, just issue of what consider mechitza briah/gruah. Then Tos innocent comment: they think only time something to discuss is if the mechitza is needed min hatorah. but if is reshut hayachid anyway. For example, something with walls on all 3 sides. idea of 4th wall only midirabanan. first mishna, with a mavoi, can put mavoi, lechi,
if curved like C, is it three walls? What about L, inside triangle, is good or not,
Chazon Ish, developed whole intuition. Less that 90 degrees, considered three walls on inside triangle... Thinks all this is included in Mishnah Berurah's diagram, (which pashut pshat is only talking about outside inner triangle to try to form a swquare.

One place Rambam writes 3 walls reshut hayachid. elsewhere writes is karmelit.

Kesef Mishna tries to suggest answer. maybe depends what it borders on 4th side. if reshut harabim diorayta, then karmelit. if borders karmelit, then is reshut hayachid.

because issue he holds, dioraytsa of nifratz lidavar haassur lo.

imagine fences around Manhattan. Then all a reshut hayachid. But GW Bridge starts 5 blocks in, in washington hights. and have tunnels inside manhatten. can leave manhatten without croseeing the mechitza.
That is an issue midirabanan. So we don;t allow you to carry inside reshut hayachid lest you leave. assume usually that completely gezaira miderabanan, a chashash.

this kesef mishnah is suggesting is such a concept diorayta. {J: i think there may even be a gemara like this...}



so rambam: sometimes reshut hayachid, s/t karmelit.

tos assumes like most rishonim, 3 mechitzot make reshut hayachid, whole tikkun is only midirabanan, and fourth wall is not maaleh velo morid.
acc to kesef mishnah, elevates to reshut hayachid. if someone carries from reshut harabbim into it, will be chayav chatat.

Innocent Tos, writes: only time gem has discussion when need mechitzot min hatorah. if put up 4th mechitza and helps not at all, that fourth wall need not worry about asi rabim umevatli mechita.

Mordecha in perek haDor im hanochri, daf nun tet, quotes maharam rutenberg. had little villiages over europe, can make an eruv, had to be huidden or goyim will stone you or take it off.
since only midirabbanan, since our little villiages are so small, not reshut harabbim. so since only midirabanan (karmelit), only need make eruv and do not worry about asi rabim.

tos only said about the 4th wall
J: Q: How can have asi rabbim on only one wall?!
 this is original source quoted in shulchan aruch., whenever faced with issue of making eruv, first must declare area working on is only a karmelit.

another reason. in poutline of shuirim, fourth section are klalim of tzurat hapesach. First of sources is mishnah berurar and biur halacha cites pri megadim, who raises new safek.
always asking, is this diorayta or dirABnanan (about tefillin black, square, etc.) so discusses tzurat hapesach. unsire if diorayta or dirabanan.
Mishna berura: but we rely oin the eruv to carry?!
pri megadim: perhaps only if issue of hotzaah is midirabanan

J:Q?: but kilyaim is diorayta, and use PEAH?!!

Chazon ish usually does not cite pri megadim, but here mishna berura cites it, so has to deal with it. dismisses pri megadim.
tes vav: a mishna. chazon ish:said the same thing i just asked.


galitzyaners metarertz pri megadim. diff bet mechitza by shabbos and eruvin vs. kilaim. to carry around, need a complete circuit. by kilyaim, not mechitza hamekefet needed. just mechitza hamafseket.

J:Q: vaguely recollect another gemara that talks about chiyuv chatat. try to find it. might actually be a pi tikra yored visotem.

so try to declare your area a karmelit.

second reason must declare. not all are concerned about asi rabbim, say peah is mechitza briah.
when have a room, area inside enclosed by the walls.

gem: frame of the door, even though door is detaches, tzurat hapesach good mechitza. and ritvah says whole nature of door is to allow people to go through. thus when make tzurat hapesach need not worry about asi rabbim.

problem of asi rabbim not bother all.
second it because mishna brura cites pri megadim then peah is dirabanan, and only hem amru vehem amru. cannot solve biblical problem

thus important to be able to identify reshut harabbim vs karmelit.

1st rule: maharam retuenberg. they made for small populations, not rehsut harabbim diorayta.
based on rashi, tos: 600,000. hotzaah also from milechet hamishkan. travelled in midbar. this horaat shaah is not horaat shaa of how travel. no, horaat shaa of mishkan. move from one place to another to construct mishkan.

gem makes distinction between ir shel rabbim or shel yachid. (J: thought meant (shabbat daf 4 or 6, eruvin 59, etc) 

all melachot learnt from the mishkon. 
many rishonim diasgree, this expression of 600,000 never appears in gemara. chachmei sfarad.
ir shel rabim/yachid. rambam translates words, not pop. by small vs large, but rather privately owned. that is explicit gemara. so ramban saud that is what mishna said.

for many centuries, practice would be to work based on maharma rutenberg in france and germany.
taz writes famous expression. so pupolar, as if a bat kol had come down from heaven and declared din. but not so, matter of dispute. strange thing everyone relies.

mishkenot yaakov. by chasidim, these eruvim very popular. he was opposed, a mitnaged. gives a list of those who do subscribe, and those who disagree. and very unhappy about all the eruvin.
he was contemporary of rav ephraim zalman margoliot. wrote a lot of seforim. rav ephraim had correspondence back and forth, he was defending all the eruvin. 

both aruch hashulchan and mishna bereura after this dispute of mishkenot yaakov... how do we rely.
biur halacha defends practice. if really dealing with issue diorayta, how can rely on lack of shishim ribo. But putting an eruv around it and whole issue is asi rabim umevatlei mechitzta. And that whole idea of asi rabbim is concern dirabanan. so since 50/50, can rely on that 50. sefeko dirabanan likula.
a little flimsy.
J:Q: didn;t we say in shiur before that not that type of safek which can be determined..?

narrow alleyway less than 16 amot wide...
our streets way more than 60.

gemara has klal. if have a roof over it, that section is not like diglei midbar so not reshut harabbim diorayta. shabbat tzadik tet(?)

here on st nicholas, thanksgiving,stretch sheets over streets for a week. (m akes a form of tikra)
sefat emet points out, even if the tikra oinly temp, area under it not considered diorayta reshut harabbim. Also, a private owned area, even if heavy traffic, not reshut harabbim diorayta.

also rule , nun tet b, only considered diorayra if mefulach. but dead end.
Benett ave not dead end. -| (lines being streets) cannot go straight. is that 
mefulash or not.

behag: only if cuts through.
some say, only if goes straight through the city with no ikum at all.

rav moshe wrote tshuva about eruv
somewqhat asked him why did you not write about mefulash.
writes said does not want to say mefulash, to dep on, since unsure thatthat is what really means;.

thinks means:

____________________________________
	|	|
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between the lines is roofed. so not reshut harabim. that is not mefulash.
further, if narrows at one point to 15 amot.

this is pele. whole thing against the shulchan aruc

eruvin, tos on amud bet that has diagram printed.

------|_______|---------------

______|--------|_____________

and at narrow is 10, else wider.


and it is exactly the oppsite of rav moshe. whole diff understanding about mefulash

cannot write a tshuva where rubs him wrong way, thinks din is diff

Ir shel yachid vs shel rabbim.
mishna has detailed halacha. rashi and tos understand means shishim ribo.
ramban does not agree, says ownership.

and says even ac to baalei hatos, that is only within city, but a road from one city to another, would agree is reshut harabim diorayta.

seems to understand tos as: reshut harabbim is highway. perhaps within city if many people, would be considered like a highway. but mamash a highway would agree.

a magen avraham in shin mem here, sk zayin(?)
???
gives rules and regulations, shel rabim,

mishna berura does not explain it either.

orchos chayim (around 1900, rabbi from sepinker): summarized few lines from tshuvos that are most important. whatever anyone said on shulchan aruch. with hosafos from meharsham.

writes on the magen avraham about highways. how makes such blanket statement. thinks driving at this idea. do not need 60 ribo. base is that a highway.

NYC, have Henry Hudson Pkway, and Harlem river drive. these are mamash highways.
could be that these two are mamash a highway. maybe that area would have 60 ribo. whatever area in manhattan would be nifratz limokom haasurt lo.

rav moshe, they say, clearly did not agree with it, bec would look out window near harlem river drive and count the num of cars. is room to argue the point that these two are mamash highways and would not need shishim ribo.

yhaber@juno.com