LISA: Laplacian In-context Spectral Analysis

We propose Laplacian In-context Spectral Analysis (LISA), a method for inference-time adaptation of Laplacian-based time-series models using only an observed prefix. LISA combines delay-coordinate embeddings and Laplacian spectral learning to produce diffusion-coordinate state representations, together with a frozen nonlinear decoder for one-step prediction. We introduce lightweight latent-space residual adapters based on either Gaussian-process regression or an attention-like Markov operator over context windows. Across forecasting and autoregressive rollout experiments, LISA improves over the frozen baseline and is often most beneficial under changing dynamics. This work links in-context adaptation to nonparametric spectral methods for dynamical systems.

Fast ($\sim N$) Diffusion Map Algorithm

In this work we explore parsimonious manifold learning techniques, specifically for Diffusion-maps. We demonstrate an algorithm and it's implementation with computational complexity (in both time and memory) of $\sim N$, with $N$ representing the number-of-samples. These techniques are essential for large-scale unsupervised learning tasks without any prior assumptions, due to sampling theorem limitations.