linearization podcasts

Séminaire - Philip Boalch : First Steps in Global Lie Theory: wild Riemann surfaces, their character varieties and topological symplectic structures

Formes automorphes (chaire internationale) - Báº£o ChÃ¢u NgÃ´

Play Episode Listen Later Apr 21, 2023 60:39

Bảo Châu NgôCollège de FranceFormes automorphes (chaire internationale)Année 2022-2023Théorie géométrique des représentationsSéminaire - Philip Boalch : First Steps in Global Lie Theory: wild Riemann surfaces, their character varieties and topological symplectic structuresRésuméI'll describe some of the story leading up to the construction of the topological symplectic structures (P.B. Oxford thesis 1999, Adv. Math. 2001) and subsequent evolution leading to the general, purely algebraic approach (B. 2002, 2009, 2014, B.-Yamakawa 2015). They generalise the holomorphic version of the symplectic structures of Narasimhan, Atiyah- Bott, Goldman involving the topological fundamental group. Our approach gives a TQFT approach to moduli of meromorphic connections on curves, involving Lie group valued moment maps.The right point of view seems to be to generalise the notion of Riemann surface to the notion of wild Riemann surface, in the spirit of Weil's 1957 Bourbaki talk, and view these symplectic varieties as their character varieties (in the spirit of Weil's 1948 text "Sur les courbes algébriques et les variétés qui s'en déduisent"). The simplest irregular example (involving the wild fundamental group) underlies the Drinfeld- Jimbo quantum group (and deformations of the underlying wild Riemann surface explain the natural G-braid group action of Lusztig). Classification of these varieties, as "global analogues of Lie groups", is still at a quite elementary stage, but a rich theory of Dynkin diagrams exists for many examples.If time permits I'll describe how these two-forms fit together with the Bottacin-Markman Poisson structure on the meromorphic Higgs bundle moduli spaces to give the wild nonabelian Hodge hyperkahler manifolds (Biquard-B. 2004). Surprisingly these hyperkahler metrics are often complete even though the corresponding harmonic maps have infinite energy. The simplest examples, certain hyperkahler four- manifolds, are the "spaces of initial conditions" of the Painlevé equations. Painlevé knew his equations were deformations of equations for elliptic functions, and so we can now see this "Painlevé simplification" as a hyperkahler rotation, from meromorphic connections to meromorphic Higgs bundles. Not only does this story encompass many famous classical integrable systems like the Lagrange top (2 poles of order 2), and those studied by Mumford (in Tata lectures on Theta II), but several of these Painlevé integrable systems were used in Seiberg-Witten's 1994 solution of 4d N=2 super Yang-Mills theory for SU(2), and one of the higher rank generalizations, introduced by Garnier in 1919 (the simplified Schlesinger system), underlies the famous Gaudin model. It was solved by Garnier in terms of abelian functions by defining spectral curves, a method rediscovered in the soliton literature in the 1970s (see e.g. Adler-Van Moerbeke 1980, Linearization of Hamiltonian systems, Jacobi varieties and representation theory, p.337, or Verdier's 1980 Séminaire Bourbaki), before being generalised by Hitchin to the case where the base curve has genus >1.Philip BoalchPhilip Boalch1991-1997: Cambridge University (B.A, Part 3, start of PhD at DPMMS)1993: summer employment drawing optical solitons (GEC Hirst research lab.)1997-1999: Oxford University, D.Phil (N. Hitchin)1999-2001: Post-doc Trieste (B. Dubrovin, M.S. Narasimhan)2001-2002: Post-doc Strasbourg (O. Biquard)2002: recruté par le CNRS2002-2003: Post-doc Columbia, New York (I. Krichever)2003-2013: CNRS, ENS Ulm2013-2014: IHES2014-2019: Orsay2019-: IMJ-PRG, Université Paris Cité

phd wild global character theory oxford math columbia lie weil oxford university goldman structures first steps tata classification hodge mumford higgs surfaces cnrs varieties lagrange garnier adv jacobi schlesinger verdier riemann hamiltonian hitchin gaudin narasimhan topological bourbaki yang mills linearization

Xanadu: The lost vision of the hypertext future (S04E04)

The Technium

Play Episode Listen Later Jan 19, 2023 106:00

Xanadu was the first hypertext project founded in 1960 by Ted Nelson. It aims to facilitate a type of media called hypermedia, which is non-sequential writing in which the reader can choose their own path through an electronic document.Links/Resources:http://www.rheingold.com/texts/tft/14.htmlhttps://en.wikipedia.org/wiki/Project_Xanaduhttps://mimix.io/en/blog/xanaduhttps://sentido-labs.com/en/library/201904240732/Xanadu%20Hypertext%20Documents.htmlhttps://www.notion.so/blog/ted-nelsonhttps://www.wired.com/1995/06/xanadu/https://xanadu.com.au/ararathttps://www.youtube.com/watch?v=-_-5cGEU9S0https://www.youtube.com/watch?v=hMKy52Intachttps://www.youtube.com/watch?v=1gPM3GqjMR4https://www.youtube.com/watch?v=hGKbRcvIZT8https://www.youtube.com/watch?v=qyzgoeeloJAhttps://www.youtube.com/watch?v=_xYwgJW7T8ohttps://jasoncrawford.org/the-lessons-of-xanaduhttps://blockprotocol.org/https://github.com/subconsciousnetwork/noosphere/blob/main/design/explainer.mdhttps://maggieappleton.com/xanadu-patternshttps://aaronzlewis.com/blog/2019/05/01/spreading-threading/https://www.zombo.com/https://stratechery.com/concept/aggregation-theory/https://maggieappleton.com/tools-for-thoughthttps://cdixon.org/2015/01/31/come-for-the-tool-stay-for-the-networkChapters:[00:00:00] Intros[00:03:22] What is Xanadu?[00:15:49] Transclusion and Bidirectionality[00:26:32] Versioning[00:29:47] Vision divorced from implementation[00:35:13] Baked in Payments[00:46:15] Hypermedia as Envisioned[00:56:20] Tiktok as Hypermedia[01:01:52] Alternative business model for the web[01:16:19] Failure to Launch[01:26:15] Linearization as a forge[01:31:51] Success of Xanadu's Vision[01:37:04] Passing the torch===== About “The Technium” =====The Technium is a weekly podcast discussing the edge of technology and what we can build with it. Each week, Sri and Wil introduce a big idea in the future of computing and extrapolate the effect it will have on the world.Follow us for new videos every week on web3, cryptocurrency, programming languages, machine learning, artificial intelligence, and more!===== Socials =====WEBSITE: https://technium.transistor.fm/SPOTIFY: https://open.spotify.com/show/1ljTFMgTeRQJ69KRWAkBy7APPLE PODCASTS: https://podcasts.apple.com/us/podcast/the-technium/id1608747545

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312 – Adding Variability, Execution Redundancy & “Essential Noise” to Practice with Equipment Modifications

The Perception & Action Podcast

Play Episode Listen Later Jul 21, 2020 22:57

A look at how modifying sports equipment (e.g., changing size, altering mass distribution or making more flexible) can enhance motor learning by adding variability and increasing movement execution redundancy. Articles: Equipment modification can enhance skill learning in young field hockey players "Essential noise" - Enhancing variability of informational constraints benefits movement control: A comment on Waddington and Adams (2003) Visual responses to changing size and to sideways motion for different directions of motion in depth: Linearization of visual responses The Effect of Variability of Practice at Execution Redundancy Level in Skilled and Novice Basketball Players Effects of manipulating ball type on youth footballers’ performance during small-sided games Blog Post: https://perceptionaction.com/simplification/ Bradman Video: https://www.youtube.com/watch?v=9o6vTXgYdqA More information: http://perceptionaction.com/ My Research Gate Page (pdfs of my articles) My ASU Web page Podcast Facebook page (videos, pics, etc) Subscribe in iOS/Apple Subscribe in Anroid/Google Support the podcast and receive bonus content Credits: The Flamin' Groovies - Shake Some Action Mark Lanegan - Saint Louis Elegy via freemusicarchive.org and jamendo.com

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Episode 3 - System Modelling

Experience Controls

Play Episode Listen Later Aug 8, 2019 24:24

In this episode we discuss one of the fundamental aspects of controls engineering: modelling. From block diagrams and Laplace Transforms to Linearization and experimental techniques, we fill you in on exactly what you need to know about this integral step in the control design process.

system modelling linearization