separation-logic-frame-rule-star-connective
IN premise — summaries/2026/08/24/wiki-Frame_problem-chunk-2.md
Created 2026-08-25T02:58:48+00:00
In separation logic, the frame rule uses the * connective ('and separately') for disjoint memory regions, allowing arbitrary unmodified memory to be added to pre/post specifications without altering the code's specification.
Summary
The separating conjunction (the * operator) guarantees that two pieces of memory don't overlap, which is what lets the frame rule work: you can tack on "and whatever else is sitting in memory that this code never touches" to a proof without having to re-derive or adjust the code's specification. This is what makes it practical to reason about programs that manipulate large, shared memory, because proofs stay local and composable instead of requiring you to enumerate every byte of the heap each time.