Hacker News with Generative AI: Topology

Foams Made Out of Felt (tanyakhovanova.com)
A foam is a finite 2-dimensional CW-complex with extra properties. This one opening sentence is already more advanced than any of my usual blog posts. Let me define a finite 2-dimensional CW-complex in layman’s terms.
A universal triangulation for flat tori (2022) (arxiv.org)
A result due to Burago and Zalgaller (1960, 1995) states that every orientable polyhedral surface, one that is obtained by gluing Euclidean polygons, has an isometric piecewise linear (PL) embedding into Euclidean space $\mathbb{E}^3$. A flat torus, resulting from the identification of the opposite sides of a Euclidean parallelogram, is a simple example of polyhedral surface. In a first part, we adapt the proof of Burago and Zalgaller, which is partially non-constructive, to produce PL isometric embeddings of flat tori. Our implementation produces embeddings with a huge number of vertices, moreover distinct for every flat torus. In a second part, based on another construction of Zalgaller (2000) and on recent works by Arnoux et al. (2021), we exhibit a universal triangulation with 2434 triangles which can be embedded linearly on each triangle in order to realize the metric of any flat torus.
Real life example of a brunnian link (twitter.com)
The binding of cosmological structures by massless topological defects (academic.oup.com)
Finite-Time Topology Identification of Delayed Complex Dynamical Networks (science.org)
Whitney Stratifications and Intersection Homology (2023) [pdf] (ethz.ch)