k-server conjecture proven true: work function algorithm achieves competitive ratio k

ctjlewis · x · 2026-09-16

A new arXiv paper by Christian Coester, Elias Koutsoupias, and Marek Zbysiński proves the long-standing k-server conjecture: a deterministic online algorithm can achieve competitive ratio k on every metric space. The proof uses the work function algorithm, representing the work function as a matrix where feasible paths map to formal expressions and each value corresponds to a determinant of k columns; requests update the representation via change of basis and row replacement, with amortized analysis via a potential function on a larger matrix.

Related event: Decades-Old k-Server Conjecture Proven on arXiv(3 posts)→

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