Ok, I’ve posted the Homework #4 key and linked it to the schedule page.

I’ve gotten a couple of questions about showing the steps for the derivations in the first part of the homework. I’ve put some notes about that in the homework key. I’m pretty sure that when I said in class that you wouldn’t need to show the steps on future homeworks, I said it was either homework #3 or homework #4 that would be the last one. However, regardless, it’s clear that not everybody caught the hedge, and so some of you did not show the individual steps, sincerely thinking that was what was being asked for. The instructions could perhaps have been clearer (though I think they were pretty clear, given that they pointed you to the model in the textbook, and the model showed the steps).

In any event, the instructions I have given the grader are to not penalize anyone specifically for not showing the steps individually. It was still important to indicate what operations happened where (Merge, Adjoin, Move, like in the model in the textbook), and I suspect that this might have been overlooked by people who didn’t draw the steps individually, but in principle it is possible to get all of the available points on the homework even if the steps weren’t given one by one.

Sorry for the confusion. Once the homework is graded and returned to you, I’m happy to discuss the outcome with anyone who wants to make the case for getting lost points back on this, if you think there’s a case to be made.