Eruvin 57a

עירובין נ״ז ע״א

Learn Eruvin 57a step by step: Aramaic beside English, every question, answer and proof colour-coded.

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Topic

The מגרש as a 'quarter' of the תחום, and the משנה's dispute about adding a קרפף to a city

Overview

The amud opens by checking the ברייתא's claim that the מגרש around a Levite city is one quarter (רביע) of the תחום. The plain arithmetic gives 8 out of 24, which is a third, so the גמרא offers three ways to reach a quarter: the city is round, רבינא says the מגרש is only along the sides, and רב אשי says it is only at the corners. רבינא objects that the פסוק says סביב, and רב אשי answers from the עולה, where 'around' means the corners. Next, רב חביבי and רב חנילאי from מחוזא challenge the round-city calculation, about jutting corners and about the 800 figure. רב אשי answers that the squaring is only imagined, and that the diagonal adds more than a quarter. A new משנה then brings a dispute about the קרפף: רבי מאיר adds one to every city, while the חכמים use it only to join nearby cities, including three villages in a triangle. In the גמרא, רבא finds the source in 'מקיר העיר וחוצה', and רב הונא and חייא בר רב disagree whether two cities get two strips or one. The סיפא of the משנה supports רב הונא, and חייא בר רב's defense continues on the next amud.

Opening lines

The steps (25)

1. StatementCalculating the size of the open space: eight units
2. ChallengeChallenge: that is a third, not a quarter
3. ResolutionAnswer: the city is round, so the open space shrinks to a quarter
4. Resolutionרבינא: a quarter, with open space only along the sides
5. Resolutionרב אשי: a quarter, with open space only at the corners
6. Challengeרבינא objects: the verse says around
7. ResolutionAround can mean around the corners, as with the altar
8. Challengeרב חביבי asks about the jutting corners
9. ResolutionWe are dealing with a round city
10. ChallengeBut cities are always squared
11. ResolutionWe only imagine it squared, we do not really square it
12. ChallengeThe numbers do not add up: a square is only a quarter bigger than a circle
13. ResolutionThe quarter rule does not cover the diagonal corners
14. Statementרבי מאיר: every city gets an added קרפף
15. Statementחכמים: the קרפף only joins two nearby cities
16. StatementThree villages in a triangle are joined by the middle one
17. QuestionWhere does the extra strip come from?
18. Responseרבא's verse: give space outside, then measure
19. Statementרב הונא: each city gets its own strip
20. Statementחייא בר רב: one shared strip
21. ChallengeThe משנה says 'קרפף' in the singular
22. Resolution'קרפף' means the rule of קרפף
23. ProofThe end of the משנה supports רב הונא
24. ChallengeIs this a refutation of חייא בר רב?
25. Resolutionחייא בר רב begins his defense