Topological spaces, manifolds, and persistent homology for understanding data shape.
5 concepts
A topological space abstracts the idea of “closeness” using open sets instead of distances, allowing geometry without measuring lengths.
A manifold is a space that locally looks like Euclidean space, stitched together by coordinate charts and smooth transition maps.
Persistent homology tracks how topological features (components, loops, voids) appear and disappear as you grow a scale parameter over a filtered simplicial complex.
Betti numbers count independent k-dimensional holes: β₀ counts connected components, β₁ counts independent loops/tunnels, and β₂ counts voids.