Someone who carries from private domain to public domain but through a neutral zone- Ben azzai says he’s exempt and rabbis say he’s obligated. Ben azzai holds that מהלך כעומד דמי- each step in considered a new stop and go and it’s therefore viewed as one transfer from private domain to neutral zone and a second transfer from neutral zone to street. But the rabbis hold that as long as you don’t stop if one continuous act and you’re obligated despite the fact you went through a neutral zone.

There are 4 types of domains. A private domain is an enclosed area- like a ditch or inside a fence- that is 4x4 tefachim. Only these areas are private domains (this is to the exclusion of r yehuda who holds that 2 full fledged parallel walls can make a private domain) A public domain is a highway or a town square, or open alleyways. (This is to the exclusion of r yehudas view that in the case of a well, when the 4 L shaped wall indentations around the well can create a private domain, and r yehuda says if the public walks through it is a public domain.) There is a “Carmelis” domain- like an open field, valley, sea, desert in our times, that is rabbincially prohibited and is in between public and private domain. There is “makom petur” that is allowable to transfer between there and public area and private area.

A desert is usually a Carmelis, but in the time when the Jews camped there, it was a public domain bc it was accessed by the public.

There is one mysterious melacha that if violated, one does not receive the death penalty. We don’t know which one it is, but it is certainly not hotzaah.