Marcin Pawlowski 5a8cc4437a

Item 5 resolved: the uncle cap is not the binding constraint under a private chain ...

With the SM1 adversary in the engine, the question item 5 could not ask is now
a measurement. It asked whether the honest-load cap needs margin when the
attack inflates orphaning, on the theory that owed uncles would defer past W.
They do not. Sweeping U x W x alpha against the attack (512 runs, N=1000,
k=256, 8 reps): at the design point and alpha = 0.3, D-hat/D reads
0.729/0.755/0.738/0.758 for U = 1/2/3/4 -- flat within noise -- and no attacked
cell reaches the 0.98 bar at any cap or either window. The honest baseline in
the same sweep reproduces sec 3.4 exactly (U=1 clears at delta=8; delta=16
needs U=2 at W=10 or W=20 at U=1), which is a useful check that the engine
adversary has not disturbed the honest regime.

Splitting the honest orphans by WHY they went unreferenced explains it. Neither
existing metric separates the two causes -- p_ref mixes them, and
deep_ref_share is 0 by construction here because the proposer's candidate
filter drops deep-fork blocks before any reference to one is proposed -- so the
script walks the tree. Countable share (first block of its fork): 97% honest,
76-81% at alpha=0.2, 59-72% at alpha=0.3. Referenced OF those: 90-93% honest,
84-93% and 80-88% under attack. The queue drains at essentially the honest rate
whatever the cap; what collapses is eligibility. An override discards a CHAIN
and only its first block has a parent on the surviving chain, so 20-40% of the
honest work destroyed is unreferenceable by construction. U governs drain
capacity for candidates that exist; it cannot manufacture eligibility.

So U = ceil(rho) + 1 stands unchanged and needs no adversarial margin -- and
the one place the cap does matter is the honest-load reason it was sized for
(U=1 -> 2 lifts the referenced-of-countable rate from 84% to 93% at
alpha = 0.2, then U=4 adds nothing).

This is the fig36 first-fork ceiling reached from an independent direction: a
per-node network simulation with real delays and a real queue, versus a
stationary MDP. Two models sharing no code, agreeing on direction and rough
size, is the strongest available evidence that the ceiling is a property of the
counting rule rather than of either model. Recorded in sec 6.6 and sec 6.8, with
the sec 6.8 structural argument corrected: it holds for orphans that are
referenceable, but a private chain buries most of them out of reach.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

2026-08-06 12:56:23 +02:00

..

tsi

Item 5 resolved: the uncle cap is not the binding constraint under a private chain

2026-08-06 12:56:23 +02:00