FA-11728 / Graph algorithm invariants / Member archive

Core decomposition stops after deleting only the initial low-degree frontier · case 03

Core decomposition stops after deleting only the initial low-degree frontier.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Return sorted vertices of the k-core of a simple undirected loopless graph, for nonnegative integer k. Repeated edges are ignored; all vertices survive k=0.

Why this case matters

A deterministic in-memory graph model isolates this invariant; no large-graph performance or production graph engine behavior is claimed.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
path cascade	`[31, 32, 33]`	`[]`	Failed

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