THEOREM: (Progress] Suppose t to be a closed, well typed term (that is, | EFt:T for some T and E). Then either t is a value, or else, for any store u such that EF H, there is some term t' and store u' such that t|u + t'lu'. Proof Sketch Straightforward induction on typing derivations, following the pattern established in topic 8. The canonical forms lemma needs two additional cases, stating that all values of type Ref T are locations, and similarly for Unit. Produce a proof of progress for simply typed calculus, augmented with Unit, the sequencing operator, and our operations on references. You do not need to reprove parts of the calculus which have not changed, but you do need to state that they haven't changed, and that the theorem still holds for them. As noted above, you need to add a couple cannonical forms. Include these new canonnical forms (you don't have to prove them). THEOREM: (Progress] Suppose t to be a closed, well typed term (that is, | EFt:T for some T and E). Then either t is a value, or else, for any store u such that EF H, there is some term t' and store u' such that t|u + t'lu'. Proof Sketch Straightforward induction on typing derivations, following the pattern established in topic 8. The canonical forms lemma needs two additional cases, stating that all values of type Ref T are locations, and similarly for Unit. Produce a proof of progress for simply typed calculus, augmented with Unit, the sequencing operator, and our operations on references. You do not need to reprove parts of the calculus which have not changed, but you do need to state that they haven't changed, and that the theorem still holds for them. As noted above, you need to add a couple cannonical forms. Include these new canonnical forms (you don't have to prove them)