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arXiv · 2602.09435

Complete CALM: A Coordination Criterion for Specifications

Joseph M. Hellerstein
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Abstract

The CALM theorem connects coordination-freedom to monotonicity, but is tied to relational transducers and set-inclusion growth. We generalize it to arbitrary concurrent specifications. A specification maps execution histories to outcome sets under a declared refinement order; we prove it admits coordination-free implementation if and only if its outcomes are monotone (\emph{Complete CALM}). The criterion subsumes CALM, CRDTs, I-confluence, and HATs as instances, enables verification of proper coordination, and yields a \emph{Complete CAP} companion: a specification admits a consistent, available, partition-tolerant implementation if and only if it is distributed-monotone.

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Joseph M. Hellerstein. 2026-02-10. Complete CALM: A Coordination Criterion for Specifications. https://arxiv.org/abs/2602.09435

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