1. box (p -> q) ..... Premise. (My notation is wrong...)
2. assumption-box-1 ... box p ....... assumption. Target is -> i...
3. dotted-box ... p -> q ... box e, 1.
4. .... p ... box e, 2. << I think maybe strictly they should be in the reverse of this order?>>
5. .... q ............ -> e, 3, 4. ..... end of dotted-box
6. box q ........ box i, 3-5, 5. .........................end of assumption box.
7. box p -> box q .................... ->i, 3-6
And on the pedantic little detail of whether the p belongs on line 3 and p ->q on line 4? (Swap so in the shorthand we have the p on the "left" and "p->q" on the right). Still looks OK to me, but maybe there's some problem stating them in reverse order?
(I only mention it because we have things like the distinction between OR-i, 1 and OR-i, 2, which is purely a question of who's left and right, or equivalently "first" and "second".)
Ja.. actually this is probably best not pursued. I'm pretty sure that we'll receive reasonably lenient treatment on a point like this. If it's a matter of bare survival or getting another small plus mark, I think you one can be sure of getting it regardless of order. If by some weird conjunction of fates one ends up being a 110-per-cent-er, maybe the mark would be axed to save us from hubris.
I'm indulging in pettifoggery here. The way they write the ->e rule, the p is on the left "upstairs". That kind of suggests that it has to arrive "first". Just like a distinction is made between left and right &e.
It really doesn't matter for practical purposes, so I'll just drop the matter, like I eventually said at the end of the original. There are more important things for us to get on with.