Entropy-Preserving Semiconjugate World Model
Implementation & benchmark of arXiv:2609.03390 — Entropy and semiconjugacy on surfaces
Source paper: Entropy and semiconjugacy on surfaces arXiv:2609.03390 ⓘ · analyzed Sep 4, 2026
AI-generated research hypothesis, automatically tested. Not peer-reviewed.
Idea description
Train a recurrent or state-space world model as a semiconjugate factorization: the high-dimensional state dynamics \(G\) must project through an encoder \(E\) to a lower-dimensional latent map \(F\), satisfying \(E\circ G\approx F\circ E\). Add a connected-fiber regularizer so states with the same latent code form geometrically coherent sets, allowing the model to discard redundant microscopic motion without discarding the entropy-carrying macroscopic dynamics.
Formulas
Mathematical statement
The paper uses a semiconjugacy \(\pi\) between maps \(g\) and \(f\), meaning \(\pi(g(x))=f(\pi(x))\) for every state \(x\). It assumes equal topological entropies \(h_{top}(g)=h_{top}(f)\), where \(h_{top}\) measures orbit-complexity growth. It establishes that each fiber \(\pi^{-1}(z)\) is connected and can be written as \(\bigcap_{k\geq 1}D_k(z)\), with closed disks \(D_{k+1}(z)\subseteq D_k(z)\). The neural adaptation replaces \(g\) by a learned full-state transition \(G_\theta\), \(f\) by a latent transition \(F_\phi\), and \(\pi\) by an encoder \(E_\psi\). The semiconjugacy residual is \(r(x)=E_\psi(G_\theta(x))-F_\phi(E_\psi(x))\). The entropy-preservation target is \(|\widehat h_T(G_\theta)-\widehat h_T(F_\phi\circ E_\psi)|\leq\delta_h\), where \(\widehat h_T\) is an empirical finite-horizon entropy-rate estimator and \(\delta_h\) is a chosen tolerance. Connected fibers are approximated by requiring interpolations between states with similar latent codes to remain close to that code.
Implementation notes
1. Integration point: use an encoder \(E_\psi\), a latent recurrent or state-space transition \(F_\phi\), and a decoder \(D_\omega\) inside an existing world model. The full-state transition \(G_\theta\) can be the observed environment transition, a separately learned high-dimensional model, or the model's recurrent update. Train the latent transition through the semiconjugacy residual rather than relying only on decoded next-state error. 2. Pseudocode: sample trajectories \(x_t\); compute \(z_t=E_\psi(x_t)\), \(\tilde z_{t+1}=F_\phi(z_t)\), and \(\hat x_{t+1}=D_\omega(\tilde z_{t+1})\). Minimize reconstruction and prediction losses plus \(\lambda_{sc}\|E_\psi(x_{t+1})-\tilde z_{t+1}\|^2\). Select pairs \(x,x'\) with nearby latent codes, draw \(\alpha\sim U[0,1]\), and penalize encoder variation along their interpolation. Estimate \(\widehat h_T\) for full and latent trajectories using the same fixed-resolution delay-coordinate or k-nearest-neighbor entropy-rate estimator, then add the entropy mismatch penalty. 3. Taken directly from the paper: the semiconjugacy identity, entropy equality, and nested-fiber principle. Estimated empirically: entropy rates, fiber connectedness, and residual magnitudes. 4. First cheap experiment: use a Hénon map embedded into 20 dimensions with nuisance oscillators and compare a standard autoencoding RNN against this model at equal latent dimension. Measure one-, ten-, and one-hundred-step prediction error, latent and full entropy rates, semiconjugacy residual, and fiber diameter after repeated refinement. The quantitative prediction is that latent entropy remains within 10-20% of full entropy while median fiber diameter decreases under refinement. If the residual is sufficiently small, long-horizon error should be governed by the latent dynamical complexity rather than nuisance dimensions. A falsification is a sharp entropy drop or fragmentation of interpolation fibers into disconnected clusters.
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.
Artifacts
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