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papers/lux-consensus-engines/sections/wave-09-comparison-with-slush-and-flare.tex
zeekay 1ecc25e9cf papers: consolidate Photon/Wave/Nova/Nebula/Ray/Field protocol stubs into lux-consensus-engines
The seven engine specifications (lux-{photon,wave,nova,nebula,prism,ray,field}-protocol)
were fragmented short notes documenting layers of the same Quasar consensus stack.
This commit merges them into a single canonical reference, lux-consensus-engines.tex,
that uses one preamble, one set of theorems, one bibliography, and one composition
chapter showing how the engines layer into the LP-020 finality pipeline.

The seven originals are reduced to single-page breadcrumb stubs pointing at the
consolidated paper; their sections/ content is preserved on disk for git history.

- new: lux-consensus-engines/ (50 pages, 646KB PDF, ~2900 lines tex)
- breadcrumbs: each original keeps cover + title + stub paragraph naming its chapter
- composition: chapter 9 records the layered contract Photon < Wave < Nova < ...
- bibliography: consolidated from the seven original thebibliography blocks
2026-05-13 01:02:25 -07:00

43 lines
2.0 KiB
TeX

\section{Comparison with Slush and Flare}
\label{sec:wave-comparison}
\subsection{Slush: No Memory}
Slush has no counters---it simply adopts the sampled majority in each round. While Slush
converges in $O(\log n)$ rounds, it provides no finality guarantee. An adversary can
continually perturb a Slush node by strategically timing equivocal responses.
\subsection{Flare: Consecutive Counters}
Flare tracks consecutive rounds of supermajority agreement. A counter $cnt$ increments
when the supermajority matches the current preference and resets to 0 on a preference
switch. Flare finalizes when $cnt \geq \beta_2$. While more robust than Slush, Flare
is vulnerable to \emph{counter reset attacks}: an adversary who can occasionally force
a preference switch resets the counter, potentially delaying finalization indefinitely.
\subsection{Wave: Cumulative Advantage}
Wave's confidence counters are cumulative---they never reset. Even if the adversary
temporarily shifts some honest nodes, the historical confidence lead is preserved.
This makes Wave strictly more robust than Flare against adaptive adversaries:
\begin{proposition}[Wave Dominates Flare]
\label{prop:dominance}
For any adversary strategy $\sigma$ and any initial configuration, the expected
finalization time under Wave is at most the expected finalization time under Flare.
\end{proposition}
\begin{proof}
Flare finalizes when $\beta_2$ \emph{consecutive} supermajority rounds occur. Wave
finalizes when $\beta_1$ \emph{total} supermajority rounds occur (for the leading color).
Since $\beta_1$ total rounds of supermajority for a fixed color always occur before
$\beta_2$ consecutive rounds (as consecutive is a stricter condition), and Wave needs
only cumulative rather than consecutive counts, Wave's finalization time is stochastically
dominated by Flare's for any $\beta_1 \leq \beta_2$.
\end{proof}
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%% 10. SECURITY CONSIDERATIONS
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