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Blackboard Shots

Recent prefixes: LiuJ Frohlich Fiedler Afeke Boyle KAL Jiang Munasinghe PoleDancing VanDerVeen Halacheva 2122-257 Gupta Abbasi TangYC Dror

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 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 Humbert Hurd Itai Izmaylov Jiang JohnsonFreyd KAL Kalka Kamnitzer Karshon Kashaev Katz Kauffman Kazhdan KhesinA Khovanov Kirk Koytcheff Kricker Kuno Kuperberg Lai Lambrechts LazyKnots Le LeD Ledvinka LeeP Leung LiBland LicataT LiuJ Martel Martins Masbaum Massuyeau Matviichuk McKay McLellan Medabalimi Meusburger Mirny MorganS Morrison Morton-Ferguson Moskovich Mracek Munasinghe Naef Nandakumar Nikolaev Olah Orr Overbay Papakonstantinou Peng Penneys PoleDancing PolyPoly-1605 Polyak Putyra Ramakrishna Rasmussen Raynor Reed Remenik Reshetikhin RobertsonM Roukema Rushworth Samuelson Sazdanovic Schaveling Scherich Schneps Sela Selmani Severa Smirnov Spreer Stein Sternberg SummerHomology2017 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 (7278, right now, with 187 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.

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.
Date-Time / Prefix Comment
211102-155035 / Afeke The structure of the cup-product matrix (9).
211026-153454 / Afeke The structure of the cup-product matrix (8).
211019-154103 / Afeke The structure of the cup-product matrix (7).
211015-165626 / LiuJ Bi-algebras, traces.
211012-153813 / Afeke The structure of the cup-product matrix (6).
211008-165201 / LiuJ Group-like elements.
211005-153836 / Afeke The structure of the cup-product matrix (5).
210928-160007 / Afeke The structure of the cup-product matrix (4).
210928-154030 / Afeke The structure of the cup-product matrix (3).
210921-160425 / Afeke The structure of the cup-product matrix (2).
210917-170117 / LiuJ The associated graded of virtual knots.
210917-153555 / Frohlich Traces and rotational virtual tangles.
210914-164623 / Afeke The structure of the cup-product matrix.
210910-170725 / LiuJ Finite generation.
210910-161101 / LiuJ Expansions and UFTIs.
210728-142257 / KAL Leonard Afeke on The Gassner Representation of String Links (4).
210728-142256 / KAL Leonard Afeke on The Gassner Representation of String Links (3).
210728-142255 / KAL Leonard Afeke on The Gassner Representation of String Links (2).
210728-142254 / KAL Leonard Afeke on The Gassner Representation of String Links.
210715-164340 / TangYC Sketch of the proof of the planar separator theorem.
210701-170112 / Afeke Completing the Kirk argument (6).
210701-170111 / Afeke Completing the Kirk argument (5).
210701-170110 / Afeke Completing the Kirk argument (4).
210630-113540 / Afeke Supervisory Meeting (2).
210630-113539 / Afeke Supervisory Meeting.
210624-165821 / Afeke Completing the Kirk argument (3).
210624-165820 / Afeke Completing the Kirk argument (2).
210624-165819 / Afeke Completing the Kirk argument.
210608-103235 / VanDerVeen Getting rid of $\hbar$.
210604-195914 / Afeke Computing cup products (4).
210528-110135 / Afeke Computing cup products (3).
210528-104400 / Afeke Computing cup products (2).
Date-Time / Prefix Comment
210517-100249 / Afeke Computing cup products.
210507-092613 / Afeke More cohomology computations (5).
210507-092100 / Afeke More cohomology computations (4).
210507-091439 / Afeke More cohomology computations (3).
210429-152437 / Afeke More cohomology computations (2).
210415-160909 / Afeke More cohomology computations.
210208-164014 / Afeke Cap products (2).
210208-163929 / Afeke Cap products.
201211-153735 / Afeke The twisted homology of $\partial X$.
201105-173823 / Afeke Reading Kirk's email (2).
201105-170312 / Afeke Reading Kirk's email.
201020-161550 / Afeke Homological representations (2).
201020-161519 / Afeke Homological representations.
200811-165033 / Afeke A split sequence?
200729-155915 / Afeke Crash recovery.
200724-160451 / Afeke A crucial statement in Kassel-Turaev (6).
200720-154713 / Afeke A crucial statement in Kassel-Turaev (5).
200720-154633 / Afeke A crucial statement in Kassel-Turaev (4).
200719-213611 / VanDerVeen $t$ and $w$ generate the centre.
200717-173256 / VanDerVeen Abbasi's argument.
200717-173027 / Abbasi A short proof of McCool's theorem (3).
200717-173026 / Abbasi A short proof of McCool's theorem (2).
200717-173025 / Abbasi A short proof of McCool's theorem.
200715-155330 / Afeke A crucial statement in Kassel-Turaev (3).
200714-145937 / Frohlich Proofs of the Weyl commutation relations (2).
200714-145936 / Frohlich Proofs of the Weyl commutation relations.
200714-125831 / Dror Verifying the Heisenberg R-matrix.
200713-171423 / Gaudreau uB injects into vB.
200713-160252 / Scherich Long for w-braids.
200710-180818 / VanDerVeen Traces.
200709-173838 / Afeke A crucial statement in Kassel-Turaev (2).
200708-160203 / Frohlich Are traces trascendental?
Date-Time / Prefix Comment
200703-175526 / VanDerVeen Zipping quadratics and pairing exterior powers.
200703-160731 / Afeke A crucial statement in Kassel-Turaev.
200702-161027 / Frohlich The Halacheva trace.
200630-181150 / Abbasi Basis conjugating automorphisms are generated by $\sigma_{ij}$ (2).
200630-181149 / Abbasi Basis conjugating automorphisms are generated by $\sigma_{ij}$.
200630-181026 / VanDerVeen Co-invariants, partial traces.
200627-114335 / Abbasi Wormholes on $S^3$ (2).
200627-114334 / Abbasi Wormholes on $S^3$.
200626-180156 / VanDerVeen Mixed-direction homomorphisms.
200626-160403 / Frohlich Partial traces.
200626-132922 / Afeke $H_1({\mathbb R}^2,{\mathbb Z}^2)$.
200626-132921 / Afeke The map $\pi_1\to H_1$ is homomorphic (3).
200625-171633 / Munasinghe Understanding $sl_{2+}^\epsilon$.
200621-180015 / VanDerVeen Heisenberg calculus (2).
200621-180014 / VanDerVeen Heisenberg calculus.
200621-160318 / Dror Switching to central variables.
200619-171742 / Scherich Combing braids.
200619-171741 / Scherich Free groups in virtual braid groups.
200619-160001 / Abbasi Towards a proof of McCool's theorem (7).
200619-160000 / Abbasi Towards a proof of McCool's theorem (6).
200619-155959 / Abbasi Towards a proof of McCool's theorem (5).
200618-180337 / VanDerVeen Spinner challenge.
200618-175701 / VanDerVeen Composition for O/U tangles.
200618-160602 / Munasinghe A genus 2 surface.
200618-100914 / Meusburger OU tangles and Hopf words.
200617-134608 / Afeke The map $\pi_1\to H_1$ is homomorphic (2).
200616-182321 / Abbasi Towards a proof of McCool's theorem (4).
200616-182320 / Abbasi Towards a proof of McCool's theorem (3).
200616-182319 / Abbasi Towards a proof of McCool's theorem (2).
200616-182318 / Abbasi Towards a proof of McCool's theorem.
200615-194307 / Scherich The Artin representation.
200615-172542 / Scherich Long's $\rho^+$ construction (2).
Date-Time / Prefix Comment
200615-153139 / Afeke The map $\pi_1\to H_1$ is homomorphic.
200612-182124 / VanDerVeen Hopf quandles?
200612-154042 / Frohlich Minor identities and Plucker coordinates.
200611-161506 / Abbasi Gauss diagrams, w-braids.
200611-155616 / Munasinghe A representation theory for ${\mathfrak{g}}_\epsilon^+$?
200610-183444 / Scherich Long's $\rho^+$ construction.
200610-170726 / Afeke Back to $\tilde{H}$ (7).
200610-170702 / Afeke Back to $\tilde{H}$ (6).
200610-091024 / Dancso A new(?) approach for solving KV degree by degree.
200609-175618 / VanDerVeen Proof of connectivity.
200608-155824 / Afeke Back to $\tilde{H}$ (5).
200603-084840 / Dancso Expansions for acyclic tangles (3).
200603-084839 / Dancso Expansions for acyclic tangles (2).
200601-170137 / Frohlich Alexander Half Density and palindromicity.
200601-153318 / Afeke Back to $\tilde{H}$ (4).
200601-100322 / Dror Searching for the perfect OU tangle / VCD.
200529-165625 / Abbasi Proof of injectivity (5).
200529-165624 / Abbasi Proof of injectivity (4).
200529-165623 / Abbasi Proof of injectivity (3).
200529-165622 / Abbasi Proof of injectivity (2).
200529-165621 / Abbasi Proof of injectivity.
200529-105142 / Scherich Generating the augmentation ideal.
200529-063354 / Dancso Expansions for acyclic tangles.
200527-160353 / Afeke Back to $\tilde{H}$ (3).
200525-154821 / Afeke Back to $\tilde{H}$ (2).
200525-154403 / Afeke Back to $\tilde{H}$.
200523-193626 / Dror Asymptotic Expansions (2).
200523-193625 / Dror Asymptotic Expansions.
200523-193429 / VanDerVeen Z is central.
200519-163033 / Abbasi Conjugators (2).
200519-162504 / Abbasi Conjugators.
200519-150133 / Gaudreau Bracelets.
Date-Time / Prefix Comment
200519-145927 / Gaudreau $F=G^2$.
200518-195509 / Dror Cinnamon Rolls with Filling.
200518-155434 / Afeke The n-puncture case.
200515-165502 / Abbasi Proving Artin's theorem (2).
200515-165501 / Abbasi Proving Artin's theorem.
200515-145722 / Gaudreau Reading Ito-Sakurai arXiv:2004.14785.
200514-081535 / Dror Garside squared.
200513-170219 / Afeke The relations between the $\alpha_n$'s (2).
200513-170218 / Afeke The relations between the $\alpha_n$'s.
200513-160010 / Dror The Golden Horseshoe.
200512-105355 / Dror Cinnamon Rolls.
200510-195225 / Dror A multi-diamond case.
200508-183718 / VanDerVeen Diamonds (2).
200508-183717 / VanDerVeen Diamonds.
200508-165606 / Dror More shtrudels.
200507-172501 / Frohlich Planar algebras and planar graphs (2).
200507-172500 / Frohlich Planar algebras and planar graphs.
200507-172329 / Dror Shielding from R1/R2.
200506-181422 / VanDerVeen Divisibility and overhangs.
200506-145051 / Gaudreau All cut systems are equivalent (2).
200506-144914 / Gaudreau All cut systems are equivalent.
200505-163633 / Abbasi The Artin representation.
200505-150712 / ThurstonD The Extraction Graph.
200504-165430 / Frohlich Circle packings, Riemann mappings, and badly drawing knots.
200504-165429 / Dror A simple extraction graph.
200504-165428 / Dror Long diamonds (4).
200504-150105 / Afeke The Abelianization of a kernel (6).
200504-113848 / Dror Long diamonds (3).
200503-151147 / Dror Long diamonds (2).
200503-151146 / Dror Long diamonds.
200501-164439 / Scherich OU and VCDs.
200430-165659 / Bellingeri Mapping class groups and graphs.

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