corpus.blog
56,966 blogs · [ { "id": "01a0deba-e925-73b9-a5b6-023750b8cd28", "title": "On internal natural isomorphisms and topological categories", "url": "https://thehighergeometer.wordpress.com/2026/09/26/on-internal-natural-isomorphisms-and-topological-categories/", "published_at": "2026-09-26T10:28:52+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e5556a9b", "title": "PSA: a category satisfying all but the smallness condition from Giraud’s theorem…", "url": "https://thehighergeometer.wordpress.com/2025/12/05/psa-a-category-satisfying-all-but-the-smallness-condition-from-girauds-theorem/", "published_at": "2025-12-05T06:32:21+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e56c8fc7", "title": "An example of a presheaf without an associated sheaf – UPDATED", "url": "https://thehighergeometer.wordpress.com/2025/12/01/an-example-of-a-presheaf-without-an-associated-sheaf/", "published_at": "2025-12-01T00:29:38+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e62e3718", "title": "A game strategy that depends on the Continuum Hypothesis?", "url": "https://thehighergeometer.wordpress.com/2025/11/19/a-game-strategy-that-depends-on-the-continuum-hypothesis/", "published_at": "2025-11-18T23:53:15+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e6cdad44", "title": "The ATLAS of Finite Groups is sound", "url": "https://thehighergeometer.wordpress.com/2025/09/27/the-atlas-of-finite-groups-is-sound/", "published_at": "2025-09-27T14:11:49+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e76160aa", "title": "Glue work instead of pasting diagrams", "url": "https://thehighergeometer.wordpress.com/2025/08/20/glue-work-instead-of-pasting-diagrams/", "published_at": "2025-08-20T03:23:35+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e808f7fd", "title": "BB(5)=47,176,870: BB(6) is … astronomically larger", "url": "https://thehighergeometer.wordpress.com/2025/07/09/bb547176870-bb6-is-astronomically-larger/", "published_at": "2025-07-09T12:32:43+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e817eb32", "title": "Infinite descent in ancient times", "url": "https://thehighergeometer.wordpress.com/2025/01/21/infinite-descent-in-ancient-times/", "published_at": "2025-01-21T00:39:14+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e8b697b5", "title": "Morphisms between abelian differentiable gerbes", "url": "https://thehighergeometer.wordpress.com/2024/11/10/morphisms-between-abelian-differentiable-gerbes/", "published_at": "2024-11-10T12:45:55+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e8f13760", "title": "Small fun observation about finite topological spaces, and some challenges", "url": "https://thehighergeometer.wordpress.com/2024/09/20/small-fun-observation-about-finite-topological-spaces-and-some-challenges/", "published_at": "2024-09-20T00:59:21+00:00" }, { "id": "01a087ec-f1a6-73c6-84f7-cb72e90c6656", "title": "Abelian differentiable gerbes – recap", "url": "https://thehighergeometer.wordpress.com/2024/09/15/abelian-differentiable-gerbes-recap/", "published_at": "2024-09-14T15:18:55+00:00" }, { "id": "01a0dec6-3cc5-7095-91a2-bd458854de10", "title": "Type-theoretic considerations in functional language software development", "url": "https://thehighergeometer.wordpress.com/2024/09/13/type-theoretic-considerations-in-functional-language-software-development/", "published_at": "2024-09-13T02:49:45+00:00" }, { "id": "01a0dec6-3cc5-7095-91a2-bd4588f003f8", "title": "Two items: a new rare high-rank elliptic curve, and a beautifully-organised orchard of Diophantine equations", "url": "https://thehighergeometer.wordpress.com/2024/09/08/two-items-a-new-rare-high-rank-elliptic-curve-and-a-beautifully-organised-orchard-of-diophantine-equations/", "published_at": "2024-09-07T14:38:38+00:00" }, { "id": "01a0dec6-3cc5-7095-91a2-bd4589c46fea", "title": "Transcription and translation of Grothendieck’s 1972 CERN talk", "url": "https://thehighergeometer.wordpress.com/2024/06/12/transcription-and-translation-of-grothendiecks-1972-cern-talk/", "published_at": "2024-06-12T07:38:21+00:00" }, { "id": "01a0dec6-3cc5-7095-91a2-bd458a1a1940", "title": "DOIs for Theory and Applications of Categories!!", "url": "https://thehighergeometer.wordpress.com/2024/06/03/dois-for-theory-and-applications-of-categories/", "published_at": "2024-06-03T06:44:15+00:00" }, { "id": "01a0dec6-3cc5-7095-91a2-bd458a629c97", "title": "Translation project: Dedekind’s second definition of finite set", "url": "https://thehighergeometer.wordpress.com/2024/03/12/translation-project-dedekinds-second-definition-of-finite-set/", "published_at": "2024-03-12T02:29:02+00:00" }, { "id": "01a0dec6-3cc5-7095-91a2-bd458b4fa9a2", "title": "Ctrl-z, 18 years later — “Yang-Mills theory for bundle gerbes” is now retracted", "url": "https://thehighergeometer.wordpress.com/2024/01/25/ctrl-z-18-years-later-yang-mills-theory-for-bundle-gerbes-is-now-retracted/", "published_at": "2024-01-25T04:13:12+00:00" }, { "id": "01a0dec6-3cc5-7095-91a2-bd458b76e0ba", "title": "DeMarr’s theorem, part 1", "url": "https://thehighergeometer.wordpress.com/2023/11/14/demarrs-theorem/", "published_at": "2023-11-14T06:15:40+00:00" }, { "id": "01a0dec6-3cc5-7095-91a2-bd458b8f743d", "title": "A fun “little” example of a crossed module", "url": "https://thehighergeometer.wordpress.com/2023/10/04/a-fun-little-example-of-a-crossed-module/", "published_at": "2023-10-04T02:25:51+00:00" }, { "id": "01a0dec6-3cc5-7095-91a2-bd458c656b51", "title": "No order-10 projective planes via SAT", "url": "https://thehighergeometer.wordpress.com/2023/08/09/no-order-10-projective-planes-via-sat/", "published_at": "2023-08-09T13:22:47+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c190852d0e2", "title": "Catching myself", "url": "https://thehighergeometer.wordpress.com/2023/06/02/catching-myself/", "published_at": "2023-06-02T07:01:55+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c1909112ec6", "title": "A Diophantine puzzle", "url": "https://thehighergeometer.wordpress.com/2023/05/25/a-diophantine-puzzle/", "published_at": "2023-05-25T06:03:10+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c1909fd6e69", "title": "Joshi’s quest", "url": "https://thehighergeometer.wordpress.com/2023/04/19/joshis-quest/", "published_at": "2023-04-18T23:31:53+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c190a1972c6", "title": "Bessis on “the secret mathematics”; teaching and research", "url": "https://thehighergeometer.wordpress.com/2023/03/10/bessis-on-the-secret-mathematics-teaching-and-research/", "published_at": "2023-03-09T23:32:12+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c190ad46c01", "title": "A study in basepoints: guest post by Kirti Joshi", "url": "https://thehighergeometer.wordpress.com/2022/11/25/a-study-in-basepoints-guest-post-by-kirti-joshi/", "published_at": "2022-11-25T01:02:38+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c190b1f8a27", "title": "Slides for Colloque Bénabou", "url": "https://thehighergeometer.wordpress.com/2022/11/18/slides-for-colloque-benabou/", "published_at": "2022-11-18T10:01:18+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c190c075e5a", "title": "Russell’s paradox: the original letter to Frege", "url": "https://thehighergeometer.wordpress.com/2022/10/11/russells-paradox-the-original-letter-to-frege/", "published_at": "2022-10-11T12:24:52+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c190c487455", "title": "The core of a Lie category is an open Lie subgroupoid", "url": "https://thehighergeometer.wordpress.com/2022/10/03/the-core-of-a-lie-category-is-an-open-lie-subgroupoid/", "published_at": "2022-10-03T06:07:25+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c190d0d1468", "title": "New paper — Rigid models for 2-gerbes I: Chern–Simons geometry", "url": "https://thehighergeometer.wordpress.com/2022/09/14/new-paper-rigid-models-for-2-gerbes-i-chern-simons-geometry/", "published_at": "2022-09-14T00:16:04+00:00" }, { "id": "01a0dee0-1420-71c8-9a05-0c190d4e2c39", "title": "Unifying ε-N and ε-δ arguments", "url": "https://thehighergeometer.wordpress.com/2022/08/22/unifying-%ce%b5-n-and-%ce%b5-%ce%b4-arguments/", "published_at": "2022-08-22T05:19:39+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d4452b27", "title": "Convergence of an infinite sum in the rationals", "url": "https://thehighergeometer.wordpress.com/2022/07/29/convergence-of-an-infinite-sun-in-the-rationals/", "published_at": "2022-07-29T06:09:59+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d45b1f4f", "title": "Mathematics as art, and as craft", "url": "https://thehighergeometer.wordpress.com/2022/06/24/mathematics-as-art-and-as-craft/", "published_at": "2022-06-24T05:34:16+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d503e4cc", "title": "When was the Joyal model structure on sSet born?", "url": "https://thehighergeometer.wordpress.com/2022/06/20/when-was-the-joyal-model-structure-on-sset-born/", "published_at": "2022-06-20T06:09:11+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d523c996", "title": "It’s a messy job, but someone had to do it: fixing all the links", "url": "https://thehighergeometer.wordpress.com/2022/04/12/its-a-messy-job-but-someone-had-to-do-it-fixing-all-the-links/", "published_at": "2022-04-12T06:20:16+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d54d254b", "title": "Homotopy equivalence of topological categories", "url": "https://thehighergeometer.wordpress.com/2022/04/07/homotopy-equivalence-of-topological-categories/", "published_at": "2022-04-07T02:21:46+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d6116d47", "title": "Geometric string structures on homogeneous spaces", "url": "https://thehighergeometer.wordpress.com/2022/04/07/geometric-string-structures-on-homogeneous-spaces/", "published_at": "2022-04-06T22:40:15+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d61a2930", "title": "Tracking an errant citation", "url": "https://thehighergeometer.wordpress.com/2022/03/04/tracking-an-errant-citation/", "published_at": "2022-03-04T02:21:03+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d6fe2539", "title": "How to be concrete when you don’t have a choice", "url": "https://thehighergeometer.wordpress.com/2022/01/13/how-to-be-concrete-when-you-dont-have-a-choice/", "published_at": "2022-01-13T03:17:50+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d7eff780", "title": "An exercise in colimits, contra Mochizuki", "url": "https://thehighergeometer.wordpress.com/2021/11/22/an-exercise-in-colimits/", "published_at": "2021-11-22T07:13:09+00:00" }, { "id": "01a0def4-7fa9-7121-b077-8978d814b5e4", "title": "A new “Brunerie number”, might be easier to calculate?", "url": "https://thehighergeometer.wordpress.com/2021/09/14/a-new-brunerie-number-might-be-easier-to-calculate/", "published_at": "2021-09-14T13:10:23+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2a598fea3", "title": "Substructural fixed-point theorems and the diagonal argument: theme and variations", "url": "https://thehighergeometer.wordpress.com/2021/08/18/substructural-fixed-point-theorems-and-the-diagonal-argument-theme-and-variations/", "published_at": "2021-08-18T05:32:39+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2a65b5ebf", "title": "Thuses", "url": "https://thehighergeometer.wordpress.com/2021/08/09/thuses/", "published_at": "2021-08-09T06:27:20+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2a723fe74", "title": "When not to say “universe”", "url": "https://thehighergeometer.wordpress.com/2021/08/06/when-not-to-say-universe/", "published_at": "2021-08-06T13:38:17+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2a7d65acd", "title": "Correction to the definition of the String crossed module, part 4: the coherence equation", "url": "https://thehighergeometer.wordpress.com/2021/07/31/correction-to-the-definition-of-the-string-crossed-module-part-4-the-coherence-equation/", "published_at": "2021-07-31T11:48:05+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2a81ca43b", "title": "Correction to the definition of the String crossed module, part 3: arriving at the contradiction, and the fix", "url": "https://thehighergeometer.wordpress.com/2021/07/29/correction-to-the-definition-of-the-string-crossed-module-part-3-arriving-at-the-contradiction-and-the-fix/", "published_at": "2021-07-29T05:45:28+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2a853c60e", "title": "Correction to the definition of the String crossed module, part 2: triangulation", "url": "https://thehighergeometer.wordpress.com/2021/07/27/correction-to-the-definition-of-the-string-crossed-module-part-2-triangulation/", "published_at": "2021-07-27T07:18:17+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2a8b5c729", "title": "Diophantine fruit", "url": "https://thehighergeometer.wordpress.com/2021/07/27/diophantine-fruit/", "published_at": "2021-07-27T03:46:11+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2a9b0784b", "title": "Correction to the definition of the String crossed module", "url": "https://thehighergeometer.wordpress.com/2021/07/23/correction-to-the-definition-of-the-string-crossed-module/", "published_at": "2021-07-23T07:27:20+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2aa56672e", "title": "The strange adventure of the Universal Coefficient Theorem in the night", "url": "https://thehighergeometer.wordpress.com/2021/05/12/the-strange-adventure-of-the-universal-coefficient-theorem-in-the-night/", "published_at": "2021-05-12T11:39:45+00:00" }, { "id": "01a0df0e-38ce-7244-9701-01b2aaf5834a", "title": "space bundle groupoid", "url": "https://thehighergeometer.wordpress.com/2021/03/15/space-bundle-groupoid/", "published_at": "2021-03-14T23:28:08+00:00" }, { "id": "01a0df26-b841-7321-8d56-df19068be392", "title": "This argument of Mochizuki doesn’t make sense to me", "url": "https://thehighergeometer.wordpress.com/2021/03/09/this-argument-of-mochizuki-doesnt-make-sense-to-me/", "published_at": "2021-03-09T01:55:10+00:00" }, { "id": "01a0df26-b842-73c1-a632-a35a0f0fadb2", "title": "Algebraic Topology: First Steps in Cohomology — videos available now!", "url": "https://thehighergeometer.wordpress.com/2021/03/05/algebraic-topology-first-steps-in-cohomology-videos-available-now/", "published_at": "2021-03-04T23:46:09+00:00" }, { "id": "01a0df26-b842-73c1-a632-a35a0f34d3dd", "title": "Algebraic topology class memes", "url": "https://thehighergeometer.wordpress.com/2021/02/24/algebraic-topology-class-memes/", "published_at": "2021-02-24T05:09:19+00:00" }, { "id": "01a0df26-b842-73c1-a632-a35a1024c6b6", "title": "Daniel Kan got his PhD done in a real hurry", "url": "https://thehighergeometer.wordpress.com/2021/01/31/daniel-kan-got-his-phd-done-in-a-real-hurry/", "published_at": "2021-01-31T08:53:50+00:00" }, { "id": "01a0df26-b842-73c1-a632-a35a10ac3f8e", "title": "Journal of Combinatorial Theory Series A editorial board quits; forms Diamond Open Access replacement", "url": "https://thehighergeometer.wordpress.com/2020/12/13/journal-of-combinatorial-theory-series-a-editorial-board-quits-forms-diamond-open-access-replacement/", "published_at": "2020-12-13T02:24:53+00:00" }, { "id": "01a0df26-b842-73c1-a632-a35a1149fb71", "title": "Update on formal anafunctors", "url": "https://thehighergeometer.wordpress.com/2020/10/20/update-on-formal-anafunctors/", "published_at": "2020-10-20T04:06:01+00:00" }, { "id": "01a0df26-b842-73c1-a632-a35a119bc960", "title": "The implications!", "url": "https://thehighergeometer.wordpress.com/2020/10/19/the-implications/", "published_at": "2020-10-19T06:45:44+00:00" }, { "id": "01a0df26-b842-73c1-a632-a35a12242793", "title": "Congratulations Roger Penrose!", "url": "https://thehighergeometer.wordpress.com/2020/10/06/congratulations-roger-penrose/", "published_at": "2020-10-06T11:36:35+00:00" }, { "id": "01a0df26-b842-73c1-a632-a35a123018d2", "title": "Elementary solution to Painlevé III", "url": "https://thehighergeometer.wordpress.com/2020/10/01/elementary-solution-to-painleve-iii/", "published_at": "2020-10-01T02:35:01+00:00" }, { "id": "01a0df26-b842-73c1-a632-a35a12ea0719", "title": "Just some Xy-pic", "url": "https://thehighergeometer.wordpress.com/2020/09/28/just-some-xy-pic/", "published_at": "2020-09-28T00:39:16+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca29c80411", "title": "Smallism", "url": "https://thehighergeometer.wordpress.com/2020/09/24/smallism/", "published_at": "2020-09-24T03:25:22+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca2a1b2e9b", "title": "Submersions", "url": "https://thehighergeometer.wordpress.com/2020/09/22/submersions/", "published_at": "2020-09-22T08:24:34+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca2a2020f5", "title": "MathOverflow question seeking answer, offering bounty", "url": "https://thehighergeometer.wordpress.com/2020/09/17/mathoverflow-question-seeking-answer-offering-bounty/", "published_at": "2020-09-17T06:41:07+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca2a3ab99b", "title": "Want to see the real secrets of set theory in YouTube format?", "url": "https://thehighergeometer.wordpress.com/2020/09/08/want-to-see-the-real-secrets-of-set-theory-in-youtube-format/", "published_at": "2020-09-07T23:47:48+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca2a64cbe1", "title": "MathOverflow links in referee reports", "url": "https://thehighergeometer.wordpress.com/2020/09/06/mathoverflow-links-in-referee-reports/", "published_at": "2020-09-06T00:46:47+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca2b4e6f18", "title": "Initiality conjecture for full Martin-Löf type theory", "url": "https://thehighergeometer.wordpress.com/2020/09/04/initiality-conjecture-for-full-martin-lof-type-theory/", "published_at": "2020-09-04T01:21:55+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca2c3b3465", "title": "She is asking the right questions", "url": "https://thehighergeometer.wordpress.com/2020/08/27/she-is-asking-the-right-questions/", "published_at": "2020-08-27T07:28:56+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca2cfd0f35", "title": "Another good maths journal, this time in analysis", "url": "https://thehighergeometer.wordpress.com/2020/08/19/another-good-maths-journal-this-time-in-analysis/", "published_at": "2020-08-19T10:19:00+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca2dc3d478", "title": "Solving restricted quadratic equations for natural number solutions is NP-complete", "url": "https://thehighergeometer.wordpress.com/2020/08/07/solving-restricted-quadratic-equations-for-natural-number-solutions-is-np-complete/", "published_at": "2020-08-07T03:33:06+00:00" }, { "id": "01a0df3a-9b3b-72db-96a6-34ca2dd72f37", "title": "Translations of technical words and phrases into French", "url": "https://thehighergeometer.wordpress.com/2020/08/05/translations-of-technical-words-and-phrases-into-french/", "published_at": "2020-08-05T10:55:23+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f61af01d", "title": "I feel accepted", "url": "https://thehighergeometer.wordpress.com/2020/08/04/i-feel-accepted/", "published_at": "2020-08-03T23:49:47+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f64191a2", "title": "Small observations on fields in Lean", "url": "https://thehighergeometer.wordpress.com/2020/07/06/small-observations-on-fields-in-lean/", "published_at": "2020-07-06T02:23:46+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f6acd996", "title": "Thank you, kind referee! :-)", "url": "https://thehighergeometer.wordpress.com/2020/07/04/thank-you-kind-referee/", "published_at": "2020-07-04T11:38:07+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f6ea48b5", "title": "Two recent research theses from my department", "url": "https://thehighergeometer.wordpress.com/2020/06/24/two-recent-research-theses-from-my-department/", "published_at": "2020-06-24T10:11:58+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f6f026ab", "title": "I’m having a long break from Twitter", "url": "https://thehighergeometer.wordpress.com/2020/06/15/im-having-a-long-break-from-twitter/", "published_at": "2020-06-15T01:20:19+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f75cbf95", "title": "MIT says no to Elsevier", "url": "https://thehighergeometer.wordpress.com/2020/06/13/mit-says-no-to-elsevier/", "published_at": "2020-06-13T03:44:05+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f84a3776", "title": "Dupuy and Hilado’s work on unravelling Mochizuki", "url": "https://thehighergeometer.wordpress.com/2020/04/27/dupuy-and-hilados-work-on-unravelling-mochizuki/", "published_at": "2020-04-27T02:48:06+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f9439b67", "title": "M5-branes and Hypothesis H", "url": "https://thehighergeometer.wordpress.com/2020/03/24/m5-branes-and-hypothesis-h/", "published_at": "2020-03-24T00:29:53+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f95facb4", "title": "A CV, I guess", "url": "https://thehighergeometer.wordpress.com/2020/03/21/a-cv-i-guess/", "published_at": "2020-03-20T20:08:41+00:00" }, { "id": "01a0df4e-5182-706c-a211-9c91f9997252", "title": "Small ideas on not-quite-covering maps", "url": "https://thehighergeometer.wordpress.com/2020/02/19/small-ideas-on-not-quite-covering-maps/", "published_at": "2020-02-19T06:41:40+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d5aed8b4", "title": "AustMS 2019 talks", "url": "https://thehighergeometer.wordpress.com/2019/12/10/austms-2019-talks/", "published_at": "2019-12-10T03:45:54+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d5f10270", "title": "Terry Tao’s first paper: “Perfect numbers”", "url": "https://thehighergeometer.wordpress.com/2019/11/27/terry-taos-first-paper-perfect-numbers/", "published_at": "2019-11-27T12:24:57+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d6c19b22", "title": "Diagonal arguments: once more with feeling", "url": "https://thehighergeometer.wordpress.com/2019/10/03/diagonals-once-more-with-feeling/", "published_at": "2019-10-03T13:13:31+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d6d29d92", "title": "The only curve with a unique focus is the parabola", "url": "https://thehighergeometer.wordpress.com/2019/09/23/the-only-curve-with-a-unique-focus-is-the-parabola/", "published_at": "2019-09-23T03:01:42+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d6e0a4e7", "title": "Third solution to writing 3 as a sum of three third powers!", "url": "https://thehighergeometer.wordpress.com/2019/09/20/third-solution-to-writing-3-as-a-sum-of-three-third-powers/", "published_at": "2019-09-20T11:40:26+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d6e3685a", "title": "Talk notes from Groupoids, Graphs and Algebras", "url": "https://thehighergeometer.wordpress.com/2019/07/02/talk-notes-from-groupoids-graphs-and-algebras/", "published_at": "2019-07-02T07:54:55+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d77387b0", "title": "Believing in (in-)consistency", "url": "https://thehighergeometer.wordpress.com/2019/06/20/believing-in-in-consistency/", "published_at": "2019-06-20T07:50:43+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d79784e8", "title": "Two Ada books", "url": "https://thehighergeometer.wordpress.com/2019/06/11/two-ada-books/", "published_at": "2019-06-11T06:06:55+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d7a7dc1a", "title": "No rational number squares to 2, after D. Zeilberger", "url": "https://thehighergeometer.wordpress.com/2019/05/19/no-rational-number-squares-to-2-after-d-zeilberger/", "published_at": "2019-05-19T13:50:56+00:00" }, { "id": "01a0df74-7669-70f3-a695-b904d8583cb8", "title": "Joyal: Arithmetisation dans le topos", "url": "https://thehighergeometer.wordpress.com/2019/05/08/joyal-arithmetisation-dans-le-topos/", "published_at": "2019-05-07T22:22:26+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f63ae862", "title": "Dupuy: computations conditional on IUT3 Corollary 3.12", "url": "https://thehighergeometer.wordpress.com/2019/05/02/dupuy-computations-conditional-on-iut3-corollary-3-12/", "published_at": "2019-05-02T11:23:13+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f67aaf79", "title": "Sans serif Hebrew", "url": "https://thehighergeometer.wordpress.com/2019/04/28/sans-serif-hebrew/", "published_at": "2019-04-28T12:46:55+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f6a2f26c", "title": "ANZAC day", "url": "https://thehighergeometer.wordpress.com/2019/04/25/anzac-day/", "published_at": "2019-04-25T00:27:34+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f76c20ae", "title": "Norway says goodbye to Elsevier", "url": "https://thehighergeometer.wordpress.com/2019/03/16/norway-says-goodbye-to-elsevier/", "published_at": "2019-03-16T00:19:10+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f785f62e", "title": "SDT book review done", "url": "https://thehighergeometer.wordpress.com/2019/03/13/sdt-book-review-done/", "published_at": "2019-03-13T03:45:54+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f7a232ae", "title": "Teaser for the new algebra/combinatorics paper", "url": "https://thehighergeometer.wordpress.com/2019/03/07/teaser-for-the-new-algebra-combinatorics-paper/", "published_at": "2019-03-07T11:36:28+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f7a2f1bf", "title": "Now on Twitter, almost", "url": "https://thehighergeometer.wordpress.com/2019/03/03/now-on-twitter-almost/", "published_at": "2019-03-03T11:35:21+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f82c5d1a", "title": "Something I wrote…", "url": "https://thehighergeometer.wordpress.com/2019/03/02/something-i-wrote/", "published_at": "2019-03-02T00:56:26+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f8842196", "title": "Rings", "url": "https://thehighergeometer.wordpress.com/2019/03/01/rings/", "published_at": "2019-03-01T04:57:43+00:00" }, { "id": "01a0df89-5d07-736b-b12b-5dd2f961c91b", "title": "The entire University of California system ditches Elsevier", "url": "https://thehighergeometer.wordpress.com/2019/03/01/the-entire-university-of-california-system-ditches-elsevier/", "published_at": "2019-03-01T04:56:42+00:00" } ] posts Claim your blog
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2026

On internal natural isomorphisms and topological categoriesoriginal ↗
26 Sept 2026

2025

PSA: a category satisfying all but the smallness condition from Giraud’s theorem…original ↗
5 Dec 2025
An example of a presheaf without an associated sheaf – UPDATEDoriginal ↗
1 Dec 2025
A game strategy that depends on the Continuum Hypothesis?original ↗
18 Nov 2025
The ATLAS of Finite Groups is soundoriginal ↗
27 Sept 2025
Glue work instead of pasting diagramsoriginal ↗
20 Aug 2025
BB(5)=47,176,870: BB(6) is … astronomically largeroriginal ↗
9 Jul 2025
Infinite descent in ancient timesoriginal ↗
21 Jan 2025

2024

Morphisms between abelian differentiable gerbesoriginal ↗
10 Nov 2024
Small fun observation about finite topological spaces, and some challengesoriginal ↗
20 Sept 2024
Abelian differentiable gerbes – recaporiginal ↗
14 Sept 2024
Type-theoretic considerations in functional language software developmentoriginal ↗
13 Sept 2024
Two items: a new rare high-rank elliptic curve, and a beautifully-organised orchard of Diophantine equationsoriginal ↗
7 Sept 2024
Transcription and translation of Grothendieck’s 1972 CERN talkoriginal ↗
12 Jun 2024
DOIs for Theory and Applications of Categories!!original ↗
3 Jun 2024
Translation project: Dedekind’s second definition of finite setoriginal ↗
12 Mar 2024
Ctrl-z, 18 years later — “Yang-Mills theory for bundle gerbes” is now retractedoriginal ↗
25 Jan 2024

2023

DeMarr’s theorem, part 1original ↗
14 Nov 2023
A fun “little” example of a crossed moduleoriginal ↗
4 Oct 2023
No order-10 projective planes via SAToriginal ↗
9 Aug 2023
Catching myselforiginal ↗
2 Jun 2023
A Diophantine puzzleoriginal ↗
25 May 2023
Joshi’s questoriginal ↗
18 Apr 2023
Bessis on “the secret mathematics”; teaching and researchoriginal ↗
9 Mar 2023

2022

A study in basepoints: guest post by Kirti Joshioriginal ↗
25 Nov 2022
Slides for Colloque Bénabouoriginal ↗
18 Nov 2022
Russell’s paradox: the original letter to Fregeoriginal ↗
11 Oct 2022
The core of a Lie category is an open Lie subgroupoidoriginal ↗
3 Oct 2022
New paper — Rigid models for 2-gerbes I: Chern–Simons geometryoriginal ↗
14 Sept 2022
Unifying ε-N and ε-δ argumentsoriginal ↗
22 Aug 2022
Convergence of an infinite sum in the rationalsoriginal ↗
29 Jul 2022
Mathematics as art, and as craftoriginal ↗
24 Jun 2022
When was the Joyal model structure on sSet born?original ↗
20 Jun 2022
It’s a messy job, but someone had to do it: fixing all the linksoriginal ↗
12 Apr 2022
Homotopy equivalence of topological categoriesoriginal ↗
7 Apr 2022
Geometric string structures on homogeneous spacesoriginal ↗
6 Apr 2022
Tracking an errant citationoriginal ↗
4 Mar 2022
How to be concrete when you don’t have a choiceoriginal ↗
13 Jan 2022

2021

An exercise in colimits, contra Mochizukioriginal ↗
22 Nov 2021
A new “Brunerie number”, might be easier to calculate?original ↗
14 Sept 2021
Substructural fixed-point theorems and the diagonal argument: theme and variationsoriginal ↗
18 Aug 2021
Thusesoriginal ↗
9 Aug 2021
When not to say “universe”original ↗
6 Aug 2021
Correction to the definition of the String crossed module, part 4: the coherence equationoriginal ↗
31 Jul 2021
Correction to the definition of the String crossed module, part 3: arriving at the contradiction, and the fixoriginal ↗
29 Jul 2021
Correction to the definition of the String crossed module, part 2: triangulationoriginal ↗
27 Jul 2021
Diophantine fruitoriginal ↗
27 Jul 2021
Correction to the definition of the String crossed moduleoriginal ↗
23 Jul 2021
The strange adventure of the Universal Coefficient Theorem in the nightoriginal ↗
12 May 2021
space bundle groupoidoriginal ↗
14 Mar 2021
This argument of Mochizuki doesn’t make sense to meoriginal ↗
9 Mar 2021
Algebraic Topology: First Steps in Cohomology — videos available now!original ↗
4 Mar 2021
Algebraic topology class memesoriginal ↗
24 Feb 2021
Daniel Kan got his PhD done in a real hurryoriginal ↗
31 Jan 2021

2020

Journal of Combinatorial Theory Series A editorial board quits; forms Diamond Open Access replacementoriginal ↗
13 Dec 2020
Update on formal anafunctorsoriginal ↗
20 Oct 2020
The implications!original ↗
19 Oct 2020
Congratulations Roger Penrose!original ↗
6 Oct 2020
Elementary solution to Painlevé IIIoriginal ↗
1 Oct 2020
Just some Xy-picoriginal ↗
28 Sept 2020
Smallismoriginal ↗
24 Sept 2020
Submersionsoriginal ↗
22 Sept 2020
MathOverflow question seeking answer, offering bountyoriginal ↗
17 Sept 2020
Want to see the real secrets of set theory in YouTube format?original ↗
7 Sept 2020
MathOverflow links in referee reportsoriginal ↗
6 Sept 2020
Initiality conjecture for full Martin-Löf type theoryoriginal ↗
4 Sept 2020
She is asking the right questionsoriginal ↗
27 Aug 2020
Another good maths journal, this time in analysisoriginal ↗
19 Aug 2020
Solving restricted quadratic equations for natural number solutions is NP-completeoriginal ↗
7 Aug 2020
Translations of technical words and phrases into Frenchoriginal ↗
5 Aug 2020
I feel acceptedoriginal ↗
3 Aug 2020
Small observations on fields in Leanoriginal ↗
6 Jul 2020
Thank you, kind referee! :-)original ↗
4 Jul 2020
Two recent research theses from my departmentoriginal ↗
24 Jun 2020
I’m having a long break from Twitteroriginal ↗
15 Jun 2020
MIT says no to Elsevieroriginal ↗
13 Jun 2020
Dupuy and Hilado’s work on unravelling Mochizukioriginal ↗
27 Apr 2020
M5-branes and Hypothesis Horiginal ↗
24 Mar 2020
A CV, I guessoriginal ↗
20 Mar 2020
Small ideas on not-quite-covering mapsoriginal ↗
19 Feb 2020

2019

AustMS 2019 talksoriginal ↗
10 Dec 2019
Terry Tao’s first paper: “Perfect numbers”original ↗
27 Nov 2019
Diagonal arguments: once more with feelingoriginal ↗
3 Oct 2019
The only curve with a unique focus is the parabolaoriginal ↗
23 Sept 2019
Third solution to writing 3 as a sum of three third powers!original ↗
20 Sept 2019
Talk notes from Groupoids, Graphs and Algebrasoriginal ↗
2 Jul 2019
Believing in (in-)consistencyoriginal ↗
20 Jun 2019
Two Ada booksoriginal ↗
11 Jun 2019
No rational number squares to 2, after D. Zeilbergeroriginal ↗
19 May 2019
Joyal: Arithmetisation dans le toposoriginal ↗
7 May 2019
Dupuy: computations conditional on IUT3 Corollary 3.12original ↗
2 May 2019
Sans serif Hebreworiginal ↗
28 Apr 2019
ANZAC dayoriginal ↗
25 Apr 2019
Norway says goodbye to Elsevieroriginal ↗
16 Mar 2019
SDT book review doneoriginal ↗
13 Mar 2019
Teaser for the new algebra/combinatorics paperoriginal ↗
7 Mar 2019
Now on Twitter, almostoriginal ↗
3 Mar 2019
Something I wrote…original ↗
2 Mar 2019
Ringsoriginal ↗
1 Mar 2019
The entire University of California system ditches Elsevieroriginal ↗
1 Mar 2019
Next