IF THE TENANTS OF A COURTYARD AND THE TENANTS ON ITS GALLERY FORGOT TO JOIN TOGETHER IN AN ‘ERUB, ANY LEVEL THAT IS HIGHER THAN TEN HANDBREADTHS BELONGS TO THE GALLERY, AND ANY LOWER LEVEL BELONGS TO THE COURTYARD
That is, any mounds or hills or piles in the courtyard the tops of which are accessible from above, say by lowering an object from a rope, belong (on Shabbat) to the residents of the upper levels:
does it not clearly follow that any area that is accessible to one by means of lowering and to the other by means of throwing is assigned to the one who uses it by means of lowering?
Lowering is not a form of working, while throwing is.
If a roof adjoins a public domain a permanent ladder is required to render it permissible for use (on Shabbat). Thus it is only a ‘permanent ladder’ that effects permissibility but not an occasional one; but why? . . .
R. Papa demurred: Is it not possible that this applies only to a roof on which many people (on weekdays) are in the habit of putting down their skull-caps and turbans?
The rooftop under discussion is not heavily trafficked. But it is, on occasion, used as a resting place and the objects set aside are light – skullcaps and turbans. Therefore to use it as a “private” location, a permanent ladder has to be set in the courtyard and not in public domain.