Leios PParams - #1317
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CIP-164 makes nine parameters of the Leios protocol governance-tunable, and the cardano-ledger proposal #5965 maps them onto the Dijkstra PParams. Add them as fields: three periods of a Leios round, four bounds on an endorser block, and the committee stake coverage and quorum stake threshold. The ranking-block max size of CIP-164's Table 3 is the existing maxBlockSize, so no field is added for it. Wire them through the mechanical companions -- the PParamsUpdate fields, applyPParamsUpdate, and the network- and security-group predicates, the two groups #5965 assigns them. AI-assisted development: Claude Opus 5 (Anthropic)
CIP-164's Table 3 makes τ < σ_c normative: the quorum stake threshold must lie strictly below the committee's stake coverage, so that a fully keyed committee can arithmetically reach a quorum. Impose it in paramsWellFormed, alongside positivity of the three Leios periods and the three Leios size bounds, which positivePParams and paramsUpdateWellFormed now list. The constraint relates two fields, so a PParamsUpdate cannot be checked for it in isolation; ppdWellFormed imposes it on the parameters an update yields. AI-assisted development: Claude Opus 5 (Anthropic)
CIP-164 now governs the voting committee by size: leiosCommitteeSize replaces leiosCommitteeStakeCoverage, and the quorum constraint τ < σ(N_c) becomes a property of the stake distribution rather than of the parameters, so paramsWellFormed can no longer impose it.
Co-authored-by: William DeMeo <williamdemeo@gmail.com>
The Use-Milliseconds amendment typed the update record's periods as Maybe Milliseconds without restoring the alias it had removed, and left the PParams record's periods at plain naturals. Restore the alias in Ledger.Prelude.Base and type the record's three periods with it.
ch1bo
marked this pull request as ready for review
September 9, 2026 17:14
ch1bo
added this pull request to stack #1318
September 9, 2026 17:16
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Re-opening of #1299, this time from the main repository.
Meanwhile, the pparams got merged into the ledger implementation already: IntersectMBO/cardano-ledger#6002