Skip to main content\(\newcommand{\powerset}[1]{\mathcal{P}(#1)}
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\)
Section C.25 V1: Hoare Logics
Synopsis.
Correctness up to now was defined on the semantics, on executions of the program.
We now develop a logic to reason about correctness without reasoning about executions.
Note that the rules of the logic have to be proven correct but that is out of scope.
Introduce basic rules of abort and assignment and informally reason about correctness.
Block and sequence rules show how free assertions are determined by other rules (assignment).
If-then-else example shows that sometimes assertions don't “add up”.
Introduce rule of consequence to strengthen preconditions and weaken postconditions.
Note that non-matching assertions can be dealt with by the consequence rule which spins off verification conditions
