cs.DSJun 2, 2026

Incremental Sheaf Cohomology on Cellular Complexes: O(1)-in-n Lazy Edit Processing under Bounded Local Geometry

Authors: Jason L. Volk

Organizations: Invariant Research

Abstract

We present an algorithmic framework for incremental maintenance of first sheaf cohomology H1(X;F)H^1(X; \mathcal{F}) on dynamically evolving 1-dimensional cellular complexes equipped with finite-dimensional cellular sheaves. The classical computation of H1H^1 via factorization of the coboundary matrix requires O(n3)O(n^3) time; when the complex evolves with a stream of mm edits, full recomputation after each edit costs O(mn3)O(mn^3). Under a bounded local geometry assumption -- bounded cell size vmaxv_{\max}, bounded stalk dimension dd, and bounded nerve degree DD -- each edit (vertex insertion, edge insertion, restriction map update) affects only a bounded set of local coboundary blocks. The algorithm therefore processes lazy streaming edits in O(1)O(1) time with respect to the total complex size nn (with cost polynomial in the local geometry parameters vmaxv_{\max}, dd, and DD, which are treated as constants independent of nn), deferring local eigensolves and Mayer-Vietoris global assembly to synchronization points (Flush). At synchronization, the maintained state agrees with the corresponding batch assembly of the partitioned sheaf model; we observe zero measured drift in all batch-verified runs (through V=106V = 10^6). We also give an amortized O(E)O(|E|) streaming construction for the cellular decomposition and discuss an adversarial algebraic-RAM barrier arguing that unpartitioned non-trivial sheaves (d2d \geq 2, non-identity restriction maps) do not admit the same locality. Experiments on Barabasi-Albert graphs with up to 5×1065 \times 10^6 vertices and 1.7×1071.7 \times 10^7 streaming edits show 35 μμs median lazy per-edit update latency (excluding flush); query time (global assembly at synchronization) is O(n)O(n) per flush in the implemented full-traversal path. Exact synchronization costs are reported separately.

Explore similar work

CardsList
  1. Towards Scalable Persistence-Based Topological Optimization

    May 9, 2026Abderrahim Bendahi, Alexandre Duplessis, Arnaud FickingerTopology OptimizationPersistent Homology