Unverified 2026

Spherical Height-Routed Multiscale Network

Implementation & benchmark of arXiv:2607.08704 — $K$-spherical horospherical averages on the Nagao quotient: tree combinatorics and exact discrepancy

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Source paper: $K$-spherical horospherical averages on the Nagao quotient: tree combinatorics and exact discrepancy arXiv:2607.08704 ⓘ · analyzed Aug 30, 2026

AI-generated research hypothesis, automatically tested. Not peer-reviewed.

Idea description

Replace an unconstrained deep routing tree by a q-ary descendant hierarchy with an explicit even height h=0,2,4,... labeling feature scale or computation depth. Train the router so that empirical occupancy of heights follows the exact even-sector law from the Nagao quotient, preventing concentration at shallow layers or unstable overuse of very deep paths.

Formulas

$$\rho^{\mathrm{ev}}(0)=\frac{q-1}{q},\qquad \rho^{\mathrm{ev}}(2m)=(q^{2}-1)q^{-2m-1},\quad m\ge 1.$$
$$\left|\operatorname{Desc}_{N}(e)\right|=q^{N}.$$
$$\mathcal{L}_{\mathrm{height}}=\tau\sum_{m=0}^{M}p_B(2m)\log\frac{p_B(2m)+\epsilon}{\rho^{\mathrm{ev}}(2m)+\epsilon},\qquad p_B(2m)=\frac{1}{B}\sum_{b=1}^{B}p_b(2m).$$
$$D_M=\sum_{m=0}^{M}\left|p_B(2m)-\rho^{\mathrm{ev}}(2m)\right|.$$

Mathematical statement

The K-spherical projection makes every observable depend only on an even height h=2m, with stationary probability rho^ev(0)=(q-1)/q and rho^ev(2m)=(q^2-1)q^(-2m-1) for m>=1. A depth-N descendant shadow has q^N terminal vertices because each step has q non-backtracking continuations. For a neural router, let p_B(2m)=B^(-1) sum_b p_b(2m) be the minibatch-averaged probability of selecting height 2m, where p_b is the routing distribution for example b. Add the KL regularizer L_height=tau sum_m p_B(2m) log((p_B(2m)+epsilon)/(rho^ev(2m)+epsilon)). The geometric tail proportional to q^(-2m) controls deep-path occupancy, while q-ary branching supplies exponentially many alternatives without requiring dense all-to-all computation.

Implementation notes

1. Integration point: construct a hierarchical MLP, Transformer feed-forward block, or MoE layer with levels m=0,...,M. Each level contains q child experts or graph modules; a router produces logits over levels or leaves, and each leaf has height h=2m. The selected path determines computation depth, feature resolution, or expert identity. For an inexpensive prototype use q=2 or 4, M=4, shared parent projections, and separate child residual adapters. 2. Pseudocode: compute router logits z_b(2m), set p_b=softmax(z_b), compute the task loss, average p_b over the minibatch to obtain p_B, evaluate rho[0]=(q-1)/q and rho[2m]=(q*q-1)*q^(-2m-1), add tau times the KL term to the task loss, and backpropagate through router and experts. Use dense soft routing initially, then switch to top-1 or top-2 routing after warmup. 3. Computed from the paper: the target shell law and q-ary descendant growth. Estimated empirically: p_B, total-variation discrepancy D_M, per-level gradient norms, activation variance, routing load, and effective FLOPs. 4. First cheap experiment: compare a six-layer residual MLP or small ViT on CIFAR-10 against an equally sized dense baseline and an unconstrained hierarchical router. Sweep tau in {0, 1e-3, 1e-2, 1e-1}. The falsifiable prediction is that constrained-router discrepancy D_M decreases during training and remains near the target law, whereas unconstrained routing collapses toward m=0 or maximum depth. For q=2, the predicted tail ratio is rho(2(m+1))/rho(2m)=1/4 for m>=1; measured tail ratios should approach 0.25. Also test inference compute: expected selected height should remain finite and approximately equal to the truncated target mean rather than growing with M. A useful failure criterion is no improvement in routing stability or a measured tail ratio differing from 0.25 by more than 20 percent after convergence.

Verification

This idea has not been verified yet.

Verification happens in two stages: Stage 1 — a mechanism check on a toy system confirms the claimed mathematical phenomenon reproduces; Stage 2 — a benchmark implements the idea on a real (small) neural network task and compares it against a tuned baseline over 8 paired seeds with a permutation test.

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