Lipschitz-Inflated Conformal Trajectory Tube
Source paper: Conformal Prediction Regions for Continuous-Time Trajectories under Random Sampling arXiv:2608.29559 ⓘ · analyzed Sep 1, 2026
AI-generated research hypothesis, automatically tested. Not peer-reviewed.
Idea description
Wrap a neural ODE, recurrent state-space model, or learned world model with a split-conformal prediction tube that is valid between irregularly sampled observations. Calibrate a pointwise residual quantile at observed times and inflate it at an unobserved time according to its distance from the nearest observed time and an estimated bound on the true and predicted trajectory slopes.
Formulas
Mathematical statement
Let X:[0,T*] -> R^d be the true trajectory, X_hat(t) the neural predictor, and T_i={t_i1,...,t_iNi} sampled times. Define L_i^cont=sup_{s != t} ||X_i(t)-X_i(s)||/|t-s| and let L_hat upper-bound the test trajectory constant with probability at least 1-alpha_L. For calibration trajectory i, define S_i=max_j ||X_i(t_ij)-X_hat_i(t_ij)|| and let q_(1-alpha) be its split-conformal quantile. If L_hat_pred bounds the predictor slope, the triangle inequality gives ||X(t)-X_hat(t)|| <= q_(1-alpha)+(L_hat+L_hat_pred) delta(t), where delta(t)=min_j |t-t_j|. The resulting tube has approximate failure probability at most alpha+alpha_L, subject to the paper's calibration split and coverage assumptions.
Implementation notes
Integrate this as an inference-time wrapper around a neural ODE, latent SSM, GRU, or world model. The base model receives irregular observations and produces a continuous prediction function X_hat(t); do not change its weights initially. Split trajectories into training and calibration sets. For every calibration trajectory, evaluate the model at its observed times, compute S_i=max_j ||X_i(t_ij)-X_hat_i(t_ij)||, and store the finite-sample conformal quantile q. Estimate L_hat from a separate high-frequency calibration set by computing the maximum finite-difference slope of the true trajectories, optionally applying a safety multiplier. Estimate L_hat_pred from dense solver evaluations of the neural predictor. At inference, for any requested time t, compute delta(t), the distance to the nearest observed input time, and return center X_hat(t) with radius q+(L_hat+L_hat_pred)delta(t). Pseudocode is: q=conformal_quantile(S); Gamma=L_hat+L_pred_hat; delta=min(abs(t-T_obs)); radius=q+Gamma*delta. The first cheap experiment is a GRU or neural ODE on noisy pendulum trajectories with randomly deleted observation times, comparing pointwise intervals against this tube. The quantitative prediction is dense-grid empirical coverage near 1-alpha-alpha_L, up to finite-sample slack, and approximately linear median radius growth with delta, with fitted slope near Gamma. Artificially using a sublinear gap inflation should cause coverage failures at the largest gaps.
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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