The σ-weighted firing laws, the σ-transfer, and the W₅ᵇ cloud bound #
The σ-weighted supply machinery for the mid-range boundedness program: two σ-shaped
firing laws, the unified σ-transfer inequality behind β = 105/128, and the bound
on the one cloud class (W₅ᵇ) that obstructs it. All certificates use the σ-weights
p_w = c/(deg w − 2) and the per-slot cost identity
(c − c/(d−2))² + (d−3)·(c/(d−2))² = c²·σ(d).
Main results #
algConn_le_two_of_sigma_apex_pair(LAW A) — an apex pair (u, vshare one neighbourgof weight 0, no cross edges, each side's non-apex σ-sum≤ 1) closes with slackcB²(Σ_A σ − 1) + cA²(Σ_B σ − 1) ≤ 0.algConn_le_two_of_sigma_cross_pair(LAW B) — a far pair with one heavy cross(h, h′)andsigS + 1/(deg h − 2) ≤ 2on each side closes (the master's leak set discounts the cross ath).- The unified σ-transfer
σ(d)·(a₃ + j) ≤ (5/4)(d − 4) + S_w: summed over heavy vertices the transfer terms cancel identically, givingΣ σ(d)·a₃ ≤ (5/4)·X + exceptions, the two exceptions being theW₅overflowsigma_transfer_w5(1/12) and the SFB-capped classes. - The
W₅ᵇcloud bound:w5big_structure,w5big_pair_mechanism,w5big_cloud_le(each big hub carries≤ 269members) andw5big_card_le(|W₅ᵇ| ≤ 5441) — unless a σ-law fires, viaW5LawConfig/w5LawConfig_closes. suppressed_ledger_beta— the assembled supply boundβ = 105/128 < 7/8forn ≥ 512.
LAW A — the σ-apex law. Two non-adjacent vertices sharing exactly one
common neighbour g, with no cross edges between the punctured
neighbourhoods and per-side punctured σ-sum at most 1, certify
algConn ≤ 2. (Weights p_w = cB/(deg w − 2) on N(u) \ {g},
q_w = cA/(deg w − 2) on N(v) \ {g}, apex at 0; the cross-scaled
magnitudes au = cB, av = cA balance the sides exactly.)
Generic σ-slot bound: for any adjacent anchor z and slot w, with
weight p = c/(deg w − 2) and master leak set N(w) ∖ insert z Z,
(c − p)² + L·p² ≤ c²·σ(deg w) + 2p².
Sharp σ-slot bound at a crossing slot: if additionally w has a
neighbour y ∈ Z distinct from z, the leak drops by one more:
(c − p)² + L·p² ≤ c²·σ(deg w) + p².
LAW B — the σ-cross law. Two non-adjacent vertices with no common
neighbour whose only cross edge can be (h, h′) (h ∈ N(u), h′ ∈ N(v)),
with the σ-slack conditions sigS u + 1/(deg h − 2) ≤ 2 and
sigS v + 1/(deg h′ − 2) ≤ 2, certify algConn ≤ 2. The master's leak set
discounts the cross edge at h and h′, leaving exactly the cross cost
2·p_h·q_{h′} ≤ cB²s_h + cA²s_{h′}, which the slack absorbs.
The unified σ-transfer (c = 5/4) #
The supply bound behind β = 105/128. Partition each heavy vertex w
(degree d ≥ 5) into a₃ degree-3 twins, f degree-4 and j heavy neighbours
(σ-mass S_w), so sigS w = f/2 + S_w. The transfer inequality
σ(d)·(a₃ + j) ≤ (5/4)(d − 4) + S_w charges σ(d) per heavy neighbour and
refunds the σ-mass received; summed over heavies the transfer terms cancel
identically, leaving Σ σ(d)·a₃ ≤ (5/4)·X + exceptions. It holds for every heavy
vertex except the W₅ overflow (1/12, sigma_transfer_w5) and the SFB-capped
usable classes (a₃ ≥ d − 2, 5 ≤ d ≤ 15). The per-degree certificates are
(d−4)(d−6+2f) ≥ 0 (non-usable), a triple-gap tie at d = 5, f = 0, and
(d−16)(d−2) ≥ 0 (saturated d ≥ 16).
σ set-sum bounds #
The set triple gap: a set of heavy σ-values summing strictly above 2
sums to at least 25/12. Either every member has degree 5 — then the sum is
(2/3)·card > 2, forcing card ≥ 4 and sum ≥ 8/3 — or some member has
degree ≥ 6, contributing ≥ 3/4 on top of ≥ 2/3 from each of the ≥ 2
others.
The neighbourhood profile of a heavy vertex #
The degree-partition of a neighbourhood: with minimum degree 3, the twins,
the degree-4 neighbours, and the heavy neighbours partition N(w).
The σ-sum decomposition: sigS w = f/2 + S_w (twins contribute σ(3) = 0,
degree-4 neighbours 1/2 each).
The pointwise transfer inequalities #
The non-usable transfer (suppressed heavy vertices): if deg w = d ≥ 5
and sigS w > 2, then σ(d)(a₃ + j) ≤ (5/4)(d−4) + S_w. The real relaxation
S_w > 2 − f/2 gives the certificate (d−4)(d−6+2f) ≥ 0 except at
d = 5, f = 0, where the triple gap S_w ≥ 25/12 makes the exact tie
10/3 = 5/4 + 25/12.
The usable transfer (uncapped, non-W₅): if deg w = d ≥ 5,
sigS w ≤ 2, a₃ ≤ d − 3, and not (d = 5 and a₃ = 2), then
σ(d)(a₃ + j) ≤ (5/4)(d−4) + S_w. Uses S_w ≥ (2/3)j and f + j ≥ 3;
certificate 3(d−4)(d−6) + 4f(d−5) + 8j(d−5) ≥ 0 for d ≥ 6, while d = 5
degenerates to j = 0, f ≥ 4 via 3f + 4j ≤ 12.
The W₅ transfer with overflow 1/12: a usable degree-5 vertex with
exactly 2 twins satisfies the transfer inequality with an extra 1/12 —
exactly, in all four sub-profiles.
The capped overflow bound: the capped classes overflow the (5/4)-rate
by total σ-mass at most 214 = 4·(25/12) + Σ (2d−1)·overflow(d).
The exchange identity and the summed transfer #
The σ-exchange identity: over the heavy set, paying σ(d_w) per heavy
neighbour equals receiving the neighbours' σ-mass — both sides count ordered
heavy-heavy adjacencies.
The summed σ-transfer (c = 5/4): on the boundary of the compact cell,
Σ_{deg w ≥ 5} σ(deg w)·|hubTwins w| ≤ (5/4)·X + (1/12)·N₅ + 214,
where N₅ counts the usable degree-5 hubs with exactly two twins (W₅) and
862 charges the capped classes only their OVERFLOW beyond the (5/4)-rate
(capped_overflow_le) — their base (5/4)(d−4) share rides in the X-term. The transfer terms
cancel
exactly via sigma_exchange.
The W₅ᵇ cloud bound #
W₅ᵇ — usable degree-5 hubs with two twins and a big neighbour — is the sole
class obstructing β < 7/8; it is bounded by a two-round pair coverage driven by
the σ-laws. Each member has neighbourhood {h, ≤4, ≤4, 3, 3} with deg h ≥ 9 the
unique non-light neighbour (w5big_structure), so LAW A / LAW B fire at side-σ
exactly 1 / slack 1/(deg h − 2). Unless a σ-law fires, every member pair has a
light-endpoint common neighbour or cross (w5big_pair_mechanism), each big hub
carrying ≤ 269 members (w5big_cloud_le), giving |W₅ᵇ| ≤ 5441
(w5big_card_le).
The W₅ᵇ class: usable degree-5 hubs with exactly two twins and a big
neighbour.
Equations
- ACMax.w5big G = {w : Fin n | G.degree w = 5 ∧ ACMax.sigS G w ≤ 2 ∧ (ACMax.hubTwins G w).card = 2 ∧ ∃ x ∈ G.neighborFinset w, 9 ≤ G.degree x}
Instances For
Structure of a W₅ᵇ member: a unique big neighbour h, every other
neighbour light, and sigS = 1 + σ(deg h) exactly.
Subset light-slot exchange: for T ⊆ W₅ᵇ and any class S of degree-≤8
vertices, Σ_{w ∈ S} |N(w) ∩ T| ≤ 4·|T|.
The law hypotheses of a member at its big hub: sigS ≤ 1 + σ(deg h)
(the erase-free LAW A side condition) and the LAW B slack
sigS + 1/(deg h − 2) ≤ 2.
The σ-law firing configuration: either a LAW A apex configuration or
a LAW B cross configuration exists (stated erase-free: the LAW A side
condition is sigS ≤ 1 + σ(deg g) and the no-cross condition is pure
adjacency).
Equations
- One or more equations did not get rendered due to their size.
Instances For
A firing configuration closes the conjecture.
The global pair mechanism: unless a σ-law fires, every member pair has a common neighbour or a cross edge with a light endpoint.
The same-cloud pair mechanism: unless a σ-law fires, every pair
sharing the big hub h has a light common neighbour or a cross edge with
both endpoints light.
A W₅ᵇ member has at most 2 degree-4 neighbours: its five slots are one
big vertex, exactly two degree-3 twins, and the rest.
The weighted light-slot exchange: summing (deg−1)·|N(w) ∩ T| over light
vertices costs 2 per twin-slot and 3 per degree-4 slot — total 10|T|.
The per-cloud cap: unless a σ-law fires, each big hub carries at most
89 members: same-cloud pairs mediate through light-only channels
(per-degree refined cells: (deg−1)²·3-weights).
The global W₅ᵇ bound: unless a σ-law fires,
|W₅ᵇ| ≤ 100 + 2200 + 1 = 2301. The P3 slot trade-off: a light x that
mediates b big neighbours spends b of its degree slots on them, so it keeps
at most deg x − b T-neighbours; balancing the b big cells (≤ 2·89 each)
against the deg x − 1 − b small cells (≤ 2·4 each) caps the per-x P3
contribution at 728 (deg 4) / 372 (deg 3).
A saturated small vertex fires the block cut. ANY vertex of degree
d ≤ 15 with at least d − 1 degree-3 twins fires
algConn_le_two_of_hub_block as soon as n ≥ 512 ≥ 2(k+1)² — in particular
a degree-3 vertex with 2 degree-3 neighbours and a degree-4 vertex with 3.
The block dichotomy: either some degree-≤ 15 vertex is twin-saturated
(and the graph fires), or EVERY vertex of degree d ≤ 15 has at most d − 2
degree-3 neighbours — degree-3 vertices at most one (M is a matching),
degree-4 vertices at most two.
The β-ledger (β = 105/128 < 7/8): on the boundary of the compact
cell, either a σ-law fires (closing the conjecture outright), or the
suppressed count obeys the sharpened supply bound
(32/21)·s ≤ (5/4)·X + 423
— i.e. s ≤ (105/128)·X + C, breaking the β = 7/8 ledger wall. The
constant is 214 (capped overflow) plus (206 + 2301)/12 (the W₅
overflow through the Moore bound and the refined cloud bound).