How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
Two dense lobes meeting at one cut vertex give
Statement refuted
The false statement FALSE: vertex connectivity, edge connectivity and minimum degree are always equal claims that vertex connectivity, edge connectivity and minimum degree always agree.
Facts & Assumptions
Given: For , take vertices spanning with the edge deleted. Add one vertex , add the edges for both , and add no edge between the two four-vertex lobes.
and are the least sizes of vertex and edge cuts (Vertex cuts, edge cuts, vertex connectivity and edge connectivity , with conventions for complete and one-vertex graphs).
is the least vertex degree (Adjacency, incidence, open and closed neighbourhoods, vertex degree, minimum degree and maximum degree).
Counterexample
The graph is connected, and deleting separates the two lobes. No deletion of zero vertices disconnects a connected graph, so .
In each lobe, and have two neighbours inside the lobe and the neighbour , so degree ; have degree inside the lobe; and has degree . Hence .
Deleting and separates the first lobe from the rest, so .
Every edge lies on a cycle. The edges and lie on the -cycle . Each internal edge incident with lies on the triangle , and each internal edge incident with lies on . Thus deleting one edge leaves an alternate path between its endpoints and cannot disconnect the graph, so .
Steps 1.3 and 1.4 give . Together with steps 1.1 and 1.2, this proves and refutes equality in both Whitney inequalities.
Remarks
Depends on
- FALSE: vertex connectivity, edge connectivity and minimum degree are always equal
- Vertex cuts, edge cuts, vertex connectivity $\kappa(G)$ and edge connectivity $\lambda(G)$, with conventions for complete and one-vertex graphs
- Adjacency, incidence, open and closed neighbourhoods, vertex degree, minimum degree and maximum degree
Used by
Nothing in the library uses this result yet.
Dependency tree · next 3 levels
Direct dependencies and their dependencies through the next three levels: 23 results over 15 levels. An arrow runs from a result to what uses it, and this result sits at the bottom with a heavier outline. Click the chart to enlarge it.
Sources
- Wolfram MathWorld, Vertex Connectivity (standard reference, not scraped)