FA-40532 / Heap invariants / Member archive

Weak heap distinguished ancestor can be above the ordinary parent · case 02

The bounded weak ancestor certificate reports an incorrect ancestor.

Member previewVariant 2 · 3 implementations · 7 checks per implementation

Case contract

A weak heap stores reverse bits r in a zero-based array. For nonroot node j, climb while j is a left child under its parent reverse bit: (j mod 2)==r[j//2]. Its distinguished ancestor is j//2 after climbing; zero has none. Report ancestor, climb path, climb count, stopping child, orientation bit, and whether direct parent suffices.

Why this case matters

This isolates an internal heap representation or priority-structure invariant using deterministic finite records.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression certificate 3	`{"ancestor": 2, "cost": 2, "direct": false, "orientation": 0, "path": [4, 2], "stop": 1}`	`{"ancestor": 0, "cost": 2, "direct": false, "orientation": 0, "path": [4, 2], "stop": 1}`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.