Linkage

Math hats (\(\mathbb{M}\)): the mathematicians of yore and their silly headwear, 2017. Later published in revised form as “MathCap History” in Math Horizons.

Carnival of Mathematics #233 (\(\mathbb{M}\)). Includes a link to my post on half-flipped binary tilings.

Impossible world (\(\mathbb{M}\), via), enormous collection of links and models regarding Escherian impossible figures.

Square carpet pattern resulting from coloring a table of bitwise ANDs by their Hamming weights.

Letterlocking: The Hidden History of the Letter (\(\mathbb{M}\)). New book by Jana Dambrogio and Daniel Starza Smith on paperfolding techniques used for paper letter security. See also their website.

Color and repetition form optical rhythms in Daniel Mullen’s geometric paintings (\(\mathbb{M}\)), often depicting three-dimensional spaces filled with transparent planes.

Indian government accused of political meddling in science prizes (\(\mathbb{M}\)): Researchers suspect they were passed over for major awards after criticizing government policies. Beyond India-specific concerns, this highlights the importance of major prizes being under the control of independent foundations and major academic societies, not of governments.

You might think that referring to a physicist named Tiziana Di Matteo would be unambiguous (\(\mathbb{M}\)) , but no: See Tiziana Di Matteo (astrophysicist) and Tiziana Di Matteo (econophysicist).

“As strongly requested by the reviewers, here we cite some references [[35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47]] although they are completely irrelevant to the present work.” (\(\mathbb{M}\)).

Lower bounds for adaptive relaxation-based algorithms for single-source shortest paths (\(\mathbb{M}\)), by Sunny Atalig, Alexander Hickerson, Arrdya Srivastav, Tingting Zheng, and Marek Chrobak, to appear at ISAAC 2024. This is part of a line of work including a paper of mine at WADS 2023 where I proved that, among shortest-path algorithms that perform relaxation steps in a fixed order, depending on the graph but not on the results of previous steps, Bellman–Ford is within a constant factor of the optimal number of steps. In arXiv:2402.10343, Jialu Hu and László Kozma eliminated the constant factor for deterministic algorithms on complete graphs, as a result showing that an older paper of mine, on a randomized version of Bellman–Ford, is strictly better than deterministic for this case. The new paper extends these results in a different direction, to algorithms whose order of operations depends (in a restricted way) on the results of previous operations, as you would want to do in any practical implementation of Bellman–Ford. For instance, once an edge has been relaxed, there’s no point in doing it again until some other step has caused the distance to its starting vertex to improve.

If you want to see this at ISAAC, in Sydney, Australia, December 8–11, you need to preregister! Registration is open only until November 29, and will not be available at the conference (via). See also the full list of ISAAC papers.

UC Irvine’s Math Community Educational Outreach program (Math CEO), aimed at middle-schoolers from diverse backgrounds and headed by professors Alessandra Pantano and Li-Sheng Tseng, has won the American Mathematical Society’s 2025 Award for an Exemplary Program or Achievement in a Mathematics Department (\(\mathbb{M}\)).

Arrangement of lines (\(\mathbb{M}\)). Another new Wikipedia Good Article, on the subdivisions of the plane formed by finite sets of lines.

David Wood asks for independent verification of a series of unpublished preprints on graceful labelings of graphs, claiming to solve several major conjectures in this area, all featuring Edinah Gnang and his “composition lemma”.