FA-40894 / Heap invariants / Member archive

Calendar queue virtual bucket uses floor division relative to origin including negative offsets · case 04

The bounded calendar placement certificate reports an incorrect virtual.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

A calendar priority queue uses integer tick origin O, positive bucket width W, and B buckets. Events [id,tick] map to virtual bucket floor((tick-O)/W), then physical index modulo B, with absolute interval boundaries retained. Report virtual and physical placements, lower and upper bounds, same-cycle eligibility relative to cursor virtual bucket, and exact-boundary events.

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	`{"boundaries": ["1", "3", "4", "5"], "cycle_eligible": ["1", "2", "3", "4"], "lower_bounds": [1, 4, 4, 7, 10, 19], "physical": [2, 3, 3, 0, 1, 0], "upper_bounds": [4, 7, 7, 10, 13, 22], "virtual": [-1, -1, 0, 0, 1, 4]}`	`{"boundaries": ["1", "3", "4", "5"], "cycle_eligible": ["1", "2", "3", "4"], "lower_bounds": [1, 4, 4, 7, 10, 19], "physical": [2, 3, 3, 0, 1, 0], "upper_bounds": [4, 7, 7, 10, 13, 22], "virtual": [-2, -1, -1, 0, 1, 4]}`	Failed

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