© | Dror Bar-Natan: Academic Pensieve: Random

Blackboard Shots

Recent prefixes: VanDerVeen LopezNeumann Lauda Afeke LiuJ Martchenkov Bosch PoleDancing SantosK Dancso Boden Kuno MurakamiJ Ohtsuki Dror Hogan

All prefixes: 08401 09240 10_327 11_1100 12_240 12_267 14_1100 15-344 15-475 16-1750 16-475 1617-257 17-1750 18-327 18S-AKT 2122-257 AKT09 AKT14 AKT17 Aarhus Abbasi Accra2010 Afeke Alekseev Alexakis Alhawaj Andersen Antolin Archibald BCHKW Bazett Beliakova Bellingeri Bettencourt Bigelow Blazejewski Boden Bosch Boyle Brin Brochier BrownF Bryden Burgos Caen Carrasco Carter Cattaneo Cheng Chterental Chu Cimasoni Conant Costantino Costello Dalvit Dancso Dema Deng Dolgushev Dror Enriquez Ens Etingof Faifman Fiedler Filmus Freedman Fresse Frohlich Frohman Furusho Gadanidis Gallagher Gaudreau Getzler Godin Gualtieri Gupta Halacheva Henriques Hillman Hirasawa Hoell Hogan Humbert Hurd Itai Izmaylov Jiang JohnsonFreyd KAL Kalka Kamnitzer Karshon Kashaev Katz Kauffman Kazhdan KhesinA Khovanov Kirk Koytcheff Kricker Kuno Kuperberg Lai Lambrechts Lauda LazyKnots Le LeD Ledvinka LeeP Leung LiBland LicataT LiuJ LopezNeumann Martchenkov Martel Martins Masbaum Massuyeau Matviichuk McKay McLellan Medabalimi Meusburger Mirny Miyazawa MorganS Morrison Morton-Ferguson Moskovich Mracek Munasinghe MurakamiJ Murphy Naef Nandakumar Nikolaev Ohtsuki Olah Orr Overbay Papakonstantinou Peng Penneys PoleDancing PolyPoly-1605 Polyak Putyra Ramakrishna Rasmussen Raynor Reed Remenik Reshetikhin RobertsonM Roukema Rushworth Samuelson SantosK Sazdanovic Schaveling Scherich Schneps Sela Selmani Severa Smirnov Spreer Stein Sternberg SummerHomology2017 Suzuki TangYC Thimotheus ThurstonD ToledanoLaredo Tsimerman VanDerVeen Vaughan Vergne VideoClub Vo WangH Willwacher Winter Yampolsky Yetter ZeilbergerN Zhang Zibrowius Zung deSilva wClips

Date-Time / Prefix Comment What? A collection of Blackboard Shots (7438, right now, with 198 prefixes), mostly taken in my office using a ceiling-mounted web camera.

Why? Mostly for my own use and for the use of the other people with whom I share blackboard space. And it is public because the easiest way to make something viewable to a number of people is to make it viewable to the whole world.

Oh no! If you found your handwriting here and you don't like it, please let me know and the relevant shot(s) will be removed, no questions asked.

How? A ceiling-mounted Logitech QuickCam Pro 9000 web camera is permanently pointed at my blackboard and connected via USB to this web server. The script bbs.php initiates a capture (using luvcview; hit "s" to shoot and "q" to quit), prompts for a file name prefix and a comment, and runs make. The makefile runs MakeDatabase.php (if necessary) to update the ShotDatabase.php. The latter file is used by index.php, which is this page, and also by show.php, used to display individual shots. The makefile also updates bbs.zip, which contains all the above mentioned scripts as well as common.php, showprefix.php, loadnew.php, random.php, the JavaScript actions.js, and the icon bbs.jpg. Finally, $\TeX$-like rendering uses MathJax (automatic on all pages but this one).

Exceptions. Some shots are taken by other means and are added manually or using loadnew.php.

240216-162057 / VanDerVeen More on bottom tangles and braided Hopf algebras (3).
240216-100055 / VanDerVeen More on bottom tangles and braided Hopf algebras (2).
240212-185211 / VanDerVeen More on bottom tangles and braided Hopf algebras.
240212-141009 / VanDerVeen KaL talk on Burau, Bottom Tangles, and Braided Hopf Algebras (5).
240212-132826 / VanDerVeen KaL talk on Burau, Bottom Tangles, and Braided Hopf Algebras (4).
240212-131639 / VanDerVeen KaL talk on Burau, Bottom Tangles, and Braided Hopf Algebras (3).
240212-130828 / VanDerVeen KaL talk on Burau, Bottom Tangles, and Braided Hopf Algebras (2).
240212-124747 / VanDerVeen KaL talk on Burau, Bottom Tangles, and Braided Hopf Algebras.
240209-155037 / LopezNeumann Kuperberg, Fox, torsion (2).
240209-155036 / LopezNeumann Kuperberg, Fox, torsion.
240207-144246 / Lauda Virtual braids and Burau.
240202-112547 / Afeke Unitarity for tangles (9).
240131-110450 / LiuJ The Blanchfield pairing.
240124-115045 / Martchenkov The fundamental forms of planar curves (2).
240124-110022 / Afeke Unitarity for tangles (8).
240117-154443 / Martchenkov The fundamental forms of planar curves.
240117-113209 / Afeke Unitarity for tangles (7).
240117-110453 / LiuJ Gaussian integrals and signatures.
240117-103736 / LiuJ Pushing and pulling (4).
240112-113439 / Afeke Unitarity for tangles (6).
240110-111619 / LiuJ Pushing and pulling (3).
240110-102345 / LiuJ Pushing and pulling (2).
231219-105334 / VanDerVeen Palindromicity in Gaussian language.
231214-100703 / Bosch Cluster algebras and quantum groups (3).
231214-100702 / Bosch Cluster algebras and quantum groups (2).
231214-100701 / Bosch Cluster algebras and quantum groups.
231211-111851 / VanDerVeen Bridges and tunnels and Alexander numbering.
231211-080441 / VanDerVeen The $T\to T^{-1}$ sequence.
231206-093134 / VanDerVeen Elementary ideals.
231129-110338 / LiuJ Pushing and pulling.
231126-081631 / LiuJ Measured Partial Quadratics (3).
231125-080639 / PoleDancing Framings and rotation numbers (5).
Date-Time / Prefix Comment
231125-080638 / PoleDancing Framings and rotation numbers (4).
231125-080637 / PoleDancing Framings and rotation numbers (3).
231122-085829 / PoleDancing Framings and rotation numbers (2).
231122-085828 / PoleDancing Framings and rotation numbers.
231121-085940 / PoleDancing Framings and rotation numbers, the injectivity of $\hat{\hbar}$.
231120-112908 / PoleDancing Don't look up!
231120-072845 / PoleDancing $\delta$ is homomorphic.
231116-121510 / LiuJ Measured Partial Quadratics (2).
231116-121509 / LiuJ Measured Partial Quadratics.
231109-152459 / Martchenkov More on $H_1(\tilde{X})$ (2).
231109-140021 / SantosK The tangle definition of ribbon knots.
231106-143156 / Afeke Unitarity for tangles (5).
231102-145504 / Martchenkov More on $H_1(\tilde{X})$.
231027-150108 / SantosK The Whirl.
231027-143119 / SantosK Why does the decomposition into conjugacy classes work?
231025-144256 / Martchenkov $H_1(\tilde{X})$ and $H_1(\tilde{X},\tilde{p})$.
231020-153136 / SantosK Meta-monoids.
231020-132732 / Afeke Unitarity for tangles (4).
231020-132003 / Afeke Unitarity for tangles (3).
231017-092051 / Dancso WKO2, again.
231013-162922 / Boden Concordance for virtual and flat knots (4).
231013-153236 / Boden Concordance for virtual and flat knots (3).
231013-143935 / Boden Concordance for virtual and flat knots (2).
231013-143157 / Boden Concordance for virtual and flat knots.
231013-135125 / SantosK Hopf algebras and tangles.
231011-161249 / Martchenkov The relation between the upper and the lower Wirtinger presentations.
231010-090000 / SantosK Planar algebras.
231006-111847 / Afeke Unitarity for tangles (2).
231005-145332 / Martchenkov The Abelianization of Dehn.
230928-155052 / SantosK PD notation and the Kauffman bracket.
230926-112555 / Afeke Unitarity for tangles.
230919-171324 / Martchenkov Invariance of Alexander formulas.
Date-Time / Prefix Comment
230912-082515 / Kuno Implementation conventions for emergent chord diagrams (4).
230911-234827 / Kuno Implementation conventions for emergent chord diagrams (3).
230905-020605 / Kuno Implementation conventions for emergent chord diagrams (2).
230905-020604 / Kuno Implementation conventions for emergent chord diagrams.
230901-020900 / MurakamiJ II and the Alexander polynomial.
230827-221831 / MurakamiJ u and v.
230815-214240 / Kuno Equations for expansions for emergent knots (4).
230815-013822 / Kuno Equations for expansions for emergent knots (3).
230815-013821 / Kuno Equations for expansions for emergent knots (2).
230815-013820 / Kuno Equations for expansions for emergent knots.
230809-022851 / Kuno The basics of finite type invariants (2).
230809-022850 / Kuno The basics of finite type invariants.
230809-022849 / Kuno The Masseyeau operation $\mu$.
230731-014244 / Ohtsuki Equivariant linking numbers (2).
230731-014243 / Ohtsuki Equivariant linking numbers.
230728-031606 / Dancso Orientation conventions.
230719-041411 / Kuno Attempts to generalize the Goldman-Turaev story (5).
230719-041410 / Kuno Attempts to generalize the Goldman-Turaev story (4).
230719-041409 / Kuno Attempts to generalize the Goldman-Turaev story (3).
230719-041408 / Kuno Attempts to generalize the Goldman-Turaev story (2).
230719-041407 / Kuno Attempts to generalize the Goldman-Turaev story.
230719-041406 / Kuno Issues with WKO2.
230718-031413 / Dror Delusions regarding KV and emergent knots (2).
230718-031412 / Dror Delusions regarding KV and emergent knots.
230718-031411 / Hogan Goldman-Turaev and Emergent Knots.
230717-221047 / Kuno KV1 and the Goldman bracket.
230717-221046 / Kuno Assembling KV solutions to higher genus KV solutions.
230713-053139 / Suzuki The Heisenberg Double and triangulations (8).
230713-053138 / Suzuki The Heisenberg Double and triangulations (7).
230713-053137 / Suzuki The Heisenberg Double and triangulations (6).
230713-053136 / Suzuki The Heisenberg Double and triangulations (5).
230712-011421 / Kuno Discussing the AKKN paper (10).
Date-Time / Prefix Comment
230711-225954 / Kuno Discussing the AKKN paper (9).
230711-225953 / Kuno Discussing the AKKN paper (8).
230711-040216 / VanDerVeen Twisted doubles (2).
230710-031833 / Kuno Discussing the AKKN paper (7).
230710-031832 / Kuno Discussing the AKKN paper (6).
230710-031831 / Kuno Discussing the AKKN paper (5).
230705-054228 / Kuno Discussing the AKKN paper (4).
230705-054227 / Kuno Discussing the AKKN paper (3).
230705-054226 / Kuno Discussing the AKKN paper (2).
230705-054225 / Kuno Discussing the AKKN paper.
230702-033714 / Suzuki The Heisenberg Double and triangulations (4).
230702-033713 / Suzuki The Heisenberg Double and triangulations (3).
230702-033712 / Suzuki The Heisenberg Double and triangulations (2).
230702-033711 / Suzuki The Heisenberg Double and triangulations.
230626-134257 / Miyazawa Problems with R4 for w-objects.
230604-131414 / Murphy Lie algebras and the 4CT.
230604-131413 / Murphy $(q+1)$-colourings.
230601-123143 / Martchenkov The Dehn presentation and the Alexander polynomial (2).
230426-114235 / LiuJ PQ Conventions (10).
230425-142328 / Martchenkov The Dehn presentation and the Alexander polynomial.
230424-162957 / LiuJ PQ Conventions (9).
230421-134216 / LiuJ PQ Conventions (8).
230420-120115 / LiuJ PQ Conventions (7).
230417-150539 / LiuJ PQ Conventions (6).
230414-114006 / LiuJ PQ Conventions (5).
230414-093729 / LiuJ PQ Conventions (4).
230412-120656 / LiuJ PQ Conventions (3).
230411-112031 / LiuJ PQ Conventions (2).
230406-032007 / Dancso The 2-pole 2-strand pentagon.
230404-021929 / Dancso Where the hell is div?
230402-224734 / Hogan Solving for $\Phi$.
230330-010211 / Dancso Thoughts on emergent tangles (2).
Date-Time / Prefix Comment
230330-010210 / Dancso Thoughts on emergent tangles.
230329-010028 / Hogan Computational techniques (2). (more...)
230329-010027 / Hogan Computational techniques.
230329-005716 / Hogan A summary of AKKN (3).
230316-004025 / Dancso Thoughts on emergent knots.
230309-191604 / Hogan A summary of AKKN (2).
230309-191603 / Hogan A summary of AKKN.
230301-170218 / LiuJ PQ Conventions.
230228-172204 / Dror Equivariant linking numbers (2).
230228-142644 / Dror Equivariant linking numbers.
230223-125050 / Martchenkov Matrices and quadratics.
230211-100908 / VanDerVeen Twisted doubles. (more...)
230206-092653 / VanDerVeen Reidemeister torsion (2).
230203-072344 / VanDerVeen Reidemeister torsion.
230116-080757 / Bosch Palindromicity (2).
230116-080756 / Bosch Palindromicity.
221214-121653 / Afeke The homology reduced Gassner representation.
221214-115337 / Dror The Gauss diagram formula for $v_2$ is invariant.
221213-100013 / Fiedler Is $V(K\setminus c)$ finite type? (4)
221213-094244 / Fiedler Is $V(K\setminus c)$ finite type? (3)
221213-093927 / Fiedler Is $V(K\setminus c)$ finite type? (2)
221213-093920 / Fiedler Is $V(K\setminus c)$ finite type?
221212-165324 / VanDerVeen Fiedler invariants.
221212-121021 / LiuJ December 2022 marathon (2).
221212-112410 / LiuJ December 2022 marathon.
221209-145832 / KAL Non commutative Gaussian elimination for $S_3$ (2).
221207-131543 / Afeke Intersection numbers in twisted homology (9).
221207-124214 / Frohlich Long rotational virtual knots.
221206-140104 / LiuJ Partial signatures (14).
221206-135447 / LiuJ Partial signatures (13).
221202-152320 / KAL Non commutative Gaussian elimination for $S_3$.
221202-150244 / KAL Gaussian elimination done right.
Date-Time / Prefix Comment
221130-124607 / LiuJ Partial signatures (12).
221130-123024 / Frohlich Fixing framings.
221129-132630 / Fiedler Polynomial invariants which can distinguish the orientations of knots (7).
221129-132625 / Fiedler Polynomial invariants which can distinguish the orientations of knots (6).
221129-132620 / Fiedler Polynomial invariants which can distinguish the orientations of knots (5).
221129-132615 / Fiedler Polynomial invariants which can distinguish the orientations of knots (4).
221129-132609 / Fiedler Polynomial invariants which can distinguish the orientations of knots (3).
221129-132605 / Fiedler Polynomial invariants which can distinguish the orientations of knots (2).
221129-132600 / Fiedler Polynomial invariants which can distinguish the orientations of knots.
221128-125305 / Afeke Intersection numbers in twisted homology (8).
221123-131443 / LiuJ Partial signatures (11).
221123-130442 / LiuJ Partial signatures (10).
221123-124953 / LiuJ Partial signatures (9).
221121-125616 / Afeke Intersection numbers in twisted homology (7).
221118-081503 / Afeke Intersection numbers in twisted homology (6).
221109-115137 / Afeke Intersection numbers in twisted homology (5).
221107-115534 / Afeke Intersection numbers in twisted homology (4).
221031-132935 / Afeke Intersection numbers in twisted homology (3).
221031-132930 / Afeke Intersection numbers in twisted homology (2).
221031-132915 / Afeke Intersection numbers in twisted homology.
221028-110613 / Boyle Finite type invariants of SNACKs (2).
221028-110604 / Boyle Finite type invariants of SNACKs.
221021-125136 / KAL The reduction lemma.
221021-122313 / KAL Homotopies (2).
221020-121604 / Jiang PVB, VB, B, PB.
221019-115945 / Afeke $\Gamma$-calculus (8).
221019-113952 / Afeke $\Gamma$-calculus (7).
221014-103631 / Munasinghe Type B Schur Algebras (5).
221014-101429 / Munasinghe Type B Schur Algebras (4).
221014-100250 / Munasinghe Type B Schur Algebras (3).
221014-093556 / Munasinghe Type B Schur Algebras (2).
221014-091646 / Munasinghe Type B Schur Algebras.
Date-Time / Prefix Comment
221005-124423 / LiuJ Partial signatures (8).
221003-131518 / Afeke $\Gamma$-calculus (6).
221003-125053 / Afeke $\Gamma$-calculus (5).
220930-130635 / KAL Homotopies.
220929-132009 / Afeke $\Gamma$-calculus (4).
220923-130803 / KAL Frobenius Algebras and TQFTs.
220921-122415 / LiuJ Partial signatures (7).
220920-131331 / Afeke $\Gamma$-calculus (3).
220916-130852 / KAL Listening to Montreal-1306.
220908-135316 / Afeke $\Gamma$-calculus (2).
220906-115552 / Afeke $\Gamma$-calculus.
220906-102305 / LiuJ Partial signatures (6).
220826-132145 / KAL Listening to Newton-1301 (5)
220826-130533 / KAL Listening to Newton-1301 (4)
220826-120937 / KAL Listening to Newton-1301 (3)
220824-162553 / LiuJ Partial signatures (5).
220823-121143 / Afeke Unitarity for groupoid representations (5).
220817-180228 / LiuJ Partial signatures (4).
220816-113312 / Afeke Unitarity for groupoid representations (4).
220816-111340 / Afeke Unitarity for groupoid representations (3).
220816-105958 / Afeke Unitarity for groupoid representations (2).
220816-104557 / Afeke Unitarity for groupoid representations.
220812-125924 / KAL Listening to Newton-1301 (2)
220812-123644 / KAL Listening to Newton-1301
220810-100547 / LiuJ Partial signatures (3).
220809-123425 / PoleDancing The flipper.
220809-104022 / Afeke Gassner as a functor (3).
220808-163148 / VanDerVeen Band Aid marathon.
220805-123801 / Frohlich Co-invariants marathon (3).
220805-104100 / Frohlich Co-invariants marathon (2).
220805-092810 / Frohlich Co-invariants marathon.
220804-164222 / LiuJ Partial signatures (2).
Date-Time / Prefix Comment
220804-155757 / LiuJ Partial signatures.
220804-130344 / Afeke Gassner as a functor (2).
220804-125927 / Afeke Gassner as a functor.
220606-144534 / Afeke Gassner for a single crossing.
220603-150005 / Halacheva Fast GPV computations (2).
220603-143552 / Halacheva Fast GPV computations.
220322-104437 / 2122-257 Closed -> exact, HW16 Q3 (3).
220322-103156 / 2122-257 Closed -> exact, HW16 Q3 (2).
220322-101624 / 2122-257 Closed -> exact, HW16 Q3.
220316-140256 / Afeke LinAlg issue.
220308-105924 / 2122-257 Fubini for layer-prseringfunctions.
220308-102037 / 2122-257 The adjoint.
220308-101424 / 2122-257 $\theta$.
220308-094753 / 2122-257 Infinitesimal Stokes' Theorem.
211215-105403 / LiuJ Listening to Dancso's talk in Montreal (2).
211215-102305 / LiuJ Listening to Dancso's talk in Montreal.
211214-122202 / Afeke Recovering Gassner from $H_1$ (3).
211214-115545 / Afeke Recovering Gassner from $H_1$ (2).
211209-140137 / Gupta The Halting Problem and Godel's Theorem (2).
211209-133932 / Gupta The Halting Problem and Godel's Theorem.
211130-172819 / Afeke Recovering Gassner from $H_1$.
211123-165941 / Afeke On to tangles! (5)
211123-164720 / Afeke On to tangles! (4)
211123-161727 / Afeke On to tangles! (3)
211116-164408 / Afeke On to tangles! (2)
211116-163123 / Afeke On to tangles!
211109-145132 / Abbasi Proof of invariance of Kashaev's signature (6).
211109-145131 / Abbasi Proof of invariance of Kashaev's signature (5).
211109-145130 / Abbasi Proof of invariance of Kashaev's signature (4).
211109-145129 / Abbasi Proof of invariance of Kashaev's signature (3).
211109-145128 / Abbasi Proof of invariance of Kashaev's signature (2).
211109-145127 / Abbasi Proof of invariance of Kashaev's signature.

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