The coarse Menger conjecture for graphs and geodesic metric spaces

Let GG be a graph or geodesic metric space, and let X,YV(G)X,Y\subseteq V(G) be two sets. For k,dNk,d\in\mathbb{N}, paths are pairwise dd-separated when each two of them are at distance at least dd.

Coarse Menger conjecture. There is a function g:N2Ng:\mathbb{N}^2\to\mathbb{N} such that for every k,dNk,d\in\mathbb{N}, every graph or geodesic metric space GG, and every two sets X,YV(G)X,Y\subseteq V(G), at least one of the following holds: there are kk disjoint XX--YY paths in GG that are pairwise at distance at least dd from each other; or there is a set ZV(G)Z\subseteq V(G) of size at most k1k-1 such that every XX--YY path is at distance at most g(k,d)g(k,d) from ZZ.

This is a coarse analogue of Menger's theorem, replacing disjointness and intersection by large separation and bounded distance. The conjecture is false in general, as indicated by the counterexamples discussed in the paper, but it holds for important classes including graphs whose cycle space is generated by cycles of bounded length, hyperbolic graphs, Cayley graphs of finitely presented groups, planar graphs with bounded face size, and complete Riemannian planes.

Sources & referencesView supporting material

Primary source

Sandra Albrechtsen, “A coarse Menger theorem for hyperbolic graphs, finitely presented groups, and more”, arXiv:2606.17605 (2026).

Additional references

4 papers in this index state this conjecture (2023–2026). The statement above is taken from the most recent of them; the others are arXiv:2605.11112, arXiv:2512.17232, arXiv:2309.07905.

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