FA-40234 / Heap invariants / Member archive

Radix redistribution advances last to the minimum of the selected bucket · case 04

The bounded radix redistribute certificate reports an incorrect threshold.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Redistribute one nonempty radix bucket with entries [id,key], all keys at least old_last. Set new_last to bucket minimum and move every entry to bit_length(key XOR new_last); preserve entry order within each destination bucket. Report threshold, assignments, bucket-zero ids, moved count, old-bucket clearing, and maximum destination.

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 2	`{"destinations": [[1, 2], [2, 0], [3, 2]], "largest_destination": 2, "moved": 3, "source_after": [], "threshold": 7, "zero_ids": [2]}`	`{"destinations": [[1, 2], [2, 0], [3, 2]], "largest_destination": 2, "moved": 3, "source_after": [], "threshold": 4, "zero_ids": [2]}`	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.