proofs
Provedquery-cover-lawdecode-attentionsoftmaxkv-cache

Bucket count (z_max − z_min)/(1/(2A)) = 2A(z_max − z_min), independent of n

For all A,zmin,zmax∈R\htmlData{mx=1}{A, \mathit{zmin}, \mathit{zmax} \in \htmlData{mx=0}{\mathbb{R}}}, if 0<A0 \mathrel{\htmlData{mx=1}{<}} \htmlData{mx=0}{A}, then

zmax−zmin12A=2A⋅(zmax−zmin)\htmlData{mx=6}{\frac{\htmlData{mx=2}{\htmlData{mx=0}{\mathit{zmax}} - \htmlData{mx=1}{\mathit{zmin}}}}{\htmlData{mx=5}{\frac{1}{\htmlData{mx=4}{2\htmlData{mx=3}{A}}}}}} \mathrel{\htmlData{mx=13}{=}} \htmlData{mx=12}{\htmlData{mx=8}{2\htmlData{mx=7}{A}} \cdot (\htmlData{mx=11}{\htmlData{mx=9}{\mathit{zmax}} - \htmlData{mx=10}{\mathit{zmin}}})}
What the notation means · or point at any symbol
RReal numbers
The real numbers: every point on the number line. (ℝ)
x ∈ TVariables
A, zmin, zmax range over real numbers: the statement must hold for every choice. ((A zmin zmax : ℝ))
<Less than
0 is strictly smaller than A. (0 < A)
=Equality
(zmax − zmin)/(1/(2 · A)) and 2 · A · (zmax − zmin) are the same. ((zmax - zmin) / (1 / (2 * A)) = 2 * A *…)
-Subtraction
zmax minus zmin. On ℕ, Lean's subtraction stops at 0: 2 − 5 = 0. (zmax - zmin)
a/bDivision
1 divided by 2 · A. In Lean, dividing by 0 gives 0. (1 / (2 * A))
·Multiplication
2 times A. (2 * A)

Per-query cost O(A·Δz + 1/ε) for a rank-1 trajectory whose covering number can be ≈ T. For T ≪ n this beats the Query-Cover Law's n·N/T, refuting its lower bound for low-rank trajectories; the corrected conjecture must involve the trajectory's dimension. Part of 'The Query-Cover Law: decode attention cost is set by where the queries go, not by how long the context is'.

How it was proved

Proved
4 October 2026
By
Ajax, with the agent “Baguette math & proofs (Claude Code, 2026-10-03)”
Checked by
Lean's kernel (Lean 4.33.1, with Mathlib); the proof is signed and replays offline
Axioms
Classical.choice, Quot.sound, propext
Proof
10 lines of Lean
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