Study Sukkah folio 4B with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
If the distance from the edge of the dug-out area to the wall was less than 3 handbreadths then it is fit, as the edge of the dug-out area is joined to the wall of the sukka based on the principle of lavud.
The Talmud asks: What is different there, in the case of a sukka with a platform in its center, that you said that it is a fit sukka if the wall is at a distance of less than 4 cubits from the edge of the platform, and what is different here that you said the wall must be at a distance of less than
The Talmud answers: There, in the case of the sukka more than 20 cubits high, where there already is a wall, but it is removed from the platform, as long as the wall is at a distance of less than 4 cubits, it is sufficient to render the sukka fit. Here, where the sukka is less than 10 handbreadt
If a sukka was more than 20 cubits high, and one built a pillar in the sukka, far from the walls, that is 10 handbreadths high, and the distance from the top of the column to the roofing was less than 20 cubits, and on the horizontal surface of the column there is a bit more than 7 by 7 handbreadth
Rava said to Abaye: That is not so, since in order to have a fit sukka we require conspicuous partitions, and there are none, as the sides of the column do not actually project above the surface.