Examples of soundness

• The main result of this subsection follows as an immediate corollary of the soundness of the typing system.

• The tool's soundness theorem is expressed in terms of the bit-level semantics of x86 programs, so its correctness depends on very few assumptions.

• If the system in figure 4 is operationally correct then, because of the soundness theorem above, the system in figure 3 is operationally correct.

• We show that the system enjoys properties like type uniqueness, subject reduction, soundness, confluence, and weak normalization.

• Section 5 then proves soundness (but not completeness) in the general case where predicates in contracts may diverge.

• The addition of recursive contracts has far-reaching implications, deeply affecting the formulation of our model and requiring different techniques for proving soundness.

• The following results are required by the proof of the soundness theorem below.

• We are interested in the soundness and conservativity issues these features raise: can we ensure modularity features do not lead to inconsistencies?