Simplicial Convolutional Filters
arXiv:2201.11720 · doi:10.1109/TSP.2022.3207045
Abstract
We study linear filters for processing signals supported on abstract topological spaces modeled as simplicial complexes, which may be interpreted as generalizations of graphs that account for nodes, edges, triangular faces etc. To process such signals, we develop simplicial convolutional filters defined as matrix polynomials of the lower and upper Hodge Laplacians. First, we study the properties of these filters and show that they are linear and shift-invariant, as well as permutation and orientation equivariant. These filters can also be implemented in a distributed fashion with a low computational complexity, as they involve only (multiple rounds of) simplicial shifting between upper and lower adjacent simplices. Second, focusing on edge-flows, we study the frequency responses of these filters and examine how we can use the Hodge-decomposition to delineate gradient, curl and harmonic frequencies. We discuss how these frequencies correspond to the lower- and the upper-adjacent couplings and the kernel of the Hodge Laplacian, respectively, and can be tuned independently by our filter designs. Third, we study different procedures for designing simplicial convolutional filters and discuss their relative advantages. Finally, we corroborate our simplicial filters in several applications: to extract different frequency components of a simplicial signal, to denoise edge flows, and to analyze financial markets and traffic networks.
arXiv comment16 pages, 13 figures, 2 tables
References in corpus (15)
- The Emerging Field of Signal Processing on Graphs: Extending High-Dimensional Data Analysis to Networks and Other Irregular Domains
- Discrete Signal Processing on Graphs
- What are higher-order networks?
- The Price of Anarchy in Transportation Networks: Efficiency and Optimality Control
- Topological Signal Processing over Simplicial Complexes
- Random Walks on Simplicial Complexes and the normalized Hodge 1-Laplacian
- Flows and Decompositions of Games: Harmonic and Potential Games
- Signal Processing on Higher-Order Networks: Livin' on the Edge ... and Beyond
- Graph-based Semi-Supervised & Active Learning for Edge Flows
- Flow Smoothing and Denoising: Graph Signal Processing in the Edge-Space
- Structure of complex networks: Quantifying edge-to-edge relations by failure-induced flow redistribution
- Finite Impulse Response Filters for Simplicial Complexes
- Signal Processing on Cell Complexes
- Metrics in the Space of High Order Networks
- Hodgelets: Localized Spectral Representations of Flows on Simplicial Complexes