To be liable for a Chatas, one must do a melocho בשוגג. The person must be mistaken not only in the beginning of the melocho but at the end of the molocho as well. For example, if someone throws an object in order to inflict a wound (forgetting it was Shabbos) if they remembered it was Shabbos before the wound was made they are exempt from a Korban. Similarly, if they threw an item in the street but remembered it was Shabbos before it landed.

If someone throws an item on Shabbos but holds on to one end, they are not liable for transferring. Like a clamp attached to a rope- even if one throws the clamp 4 Amos they are exempt bc they’re still holding the rope.

If someone threw an object and instead of the hanacha happening from their own force, something else intercepts the hanacha. A dog catches it, or someone else, or it got burned by a fire- in these cases the thrower is exempt bc the hanacha is not from his force.

There’s a dispute between r gamliel and Rabanan about ידיעה לחצי שיעור- if awareness in middle of Shogeg sin splits up the two parts or not. For example, someone wrote one letter on Shabbos bshogeg then realized the mistake. If they subsequently forget again, would it combine to the first letter? R gamliel says it would and Rabban say it would Not. Someone who carried two Amos bshogeg, then 2 Amos במזיד, then 2 more Amos בשוגג- even r gamliel agrees the two parts of Shogeg do not combine bc in this case a full size (4 Amos) happened during meizid state. In contrast, if someone threw 6 Amos- first 2 Amos they were Shogeg, next 2 meizid and last 2 Shogeg- even Rabban agree they are liable bc when throwing he can’t stop it after 4 Amos once it’s thrown so his awareness in the middle does not divide.

Even though there is a rule than hanacha is only on place of 4 tefach, but if one intends specifically for object to land on certain spot they are liable whatever the size.

The shiur for melocho or boneh- building- is any tiny amount. In the mishkan, if a plank of wood get a worm in it and bored a hole, they’d pour some lead to seal the hole. Similarly, a homeowner with a hole in the wall may seal it with clay.

There’s 3 levels when building a wall. The foundation one is a liable for firmly placing the stones securely in the ground. The next few rows it’s boneh only if the bricks are cemented as well. The top level even just placing brick is boneh.

Rav holds even minimal acts of fixing items can be boneh, while Shmuel holds minimal acts are not boneh. 3 examples- chiseling a stone is bones like rav and only מכה בפטיש like shmeul. Making small hole in chicken coop to let out fumes. Or Wedging a peg in the cavity of a hoe to secure the two parts.