© | Dror Bar-Natan: Academic Pensieve: Random

Blackboard Shots

Recent prefixes: Afeke VanDerVeen Abbasi Frohlich Dror Gaudreau Scherich Munasinghe Meusburger Dancso ThurstonD Bellingeri Chterental Fresse Ens Stein

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 AKT09 AKT14 AKT17 Aarhus Abbasi Accra2010 Afeke Alekseev Alexakis Alhawaj Andersen Antolin Archibald BCHKW Bazett Beliakova Bellingeri Bettencourt Bigelow Blazejewski Boden 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 Halacheva Henriques Hillman Hirasawa Hoell Humbert Hurd Itai Izmaylov 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 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 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 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 (7137, right now, with 180 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.

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?
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 $sl_{2+}^\epsilon$.
Date-Time / Prefix Comment
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).
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).
Date-Time / Prefix Comment
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.
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).
Date-Time / Prefix Comment
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.
200430-165512 / Dror Chterental's counter(?)-example (2).
200429-163709 / Afeke The Abelianization of a kernel (5).
200429-135311 / Dror Chterental's counter(?)-example.
200429-124522 / Frohlich Braid-like and cyclic R-moves.
200428-210337 / Dancso The injectivity of $\bar{\Gamma}$ and the Diamond Lemma (2).
200428-210336 / Dancso The injectivity of $\bar{\Gamma}$ and the Diamond Lemma.
200428-141031 / Dror Another divisibility case.
200426-140132 / Dror A bug in the divisibility lemma (2).
200425-195059 / Dror A bug in the divisibility lemma.
200425-192517 / Chterental Some diamonds (3).
200425-173535 / Chterental Some diamonds (2).
200425-172053 / Chterental Some diamonds.
200425-111054 / Gaudreau Kamada's construction (3).
Date-Time / Prefix Comment
200425-111053 / Dror Lemmas about crossing number.
200424-160332 / Frohlich Random.
200424-150653 / Scherich A multivariable LKB?
200424-150652 / Dror Dealing with R1 (2).
200424-150651 / Dror Dealing with R1.
200423-171420 / Afeke The Abelianization of a kernel (4).
200423-171419 / Afeke Implementing Fox derivatives.
200422-151530 / Frohlich Yarn balls and complexity.
200421-180229 / VanDerVeen The Diamond Lemma.
200420-095233 / Dror R1 issues.
200417-180125 / VanDerVeen Riemann mappings and mapping-classs-vector-fields.
200417-170148 / Afeke Back to $\tilde{H}$.
200417-170053 / Afeke The Abelianization of a kernel (3).
200417-165539 / Afeke The Abelianization of a kernel (2).
200417-165412 / Dror $\beta|T$.
200415-170946 / Afeke The Abelianization of a kernel.
200415-142703 / Dror Every UO fixing process terminates.
200414-182305 / VanDerVeen Aiming to separate vOU tangles with quantum invariants.
200414-124207 / Dror A possible problem case.
200411-180721 / VanDerVeen Virtual surgeries.
200411-144200 / Afeke $\tilde{H}$ in Kassel-Turaev 3.2.1 (2).
200408-181534 / VanDerVeen Random
200407-152413 / Afeke $\tilde{H}$ in Kassel-Turaev 3.2.1.
200405-185919 / VanDerVeen The injectivity of PvB->OU, following Chterental (3).
200405-185918 / VanDerVeen The injectivity of PvB->OU, following Chterental (2).
200405-185917 / VanDerVeen The injectivity of PvB->OU, following Chterental.
200405-152214 / Dror Uniqueness of OU forms?
200404-172259 / Gaudreau Kamada's construction (2).
200404-172258 / Gaudreau Kamada's construction.
200404-150338 / Afeke Relative homology (2).
200404-150149 / Afeke Relative homology.
200403-160356 / Dror Reductive OU tangles (2).
Date-Time / Prefix Comment
200403-160355 / Dror Reductive OU tangles.
200401-151306 / Scherich An up-then-down braid equivalence.
200401-151305 / Dror Random (2).
200330-192515 / VanDerVeen Associators and 6j symbols.
200330-192432 / VanDerVeen Universal $sl_2$ projectors.
200330-192229 / VanDerVeen OU tangles and braids.
200330-174054 / Dror Random.
200330-160014 / Afeke Back to Kassel-Turaev 3.2.1 (3).
200330-155613 / Afeke Back to Kassel-Turaev 3.2.1 (2).
200330-152542 / Afeke Back to Kassel-Turaev 3.2.1.
200329-131536 / Dror An up-then-down braid relation.
200328-154555 / Afeke The intersection form (2).
200328-153721 / Afeke The intersection form.
200327-194535 / VanDerVeen Connected diagrams, 1PI.
200327-194405 / VanDerVeen The Sweedler Algebra.
200327-160234 / Afeke The boundary of an intersection (2).
200327-160233 / Dror Random.
200324-154112 / Afeke The boundary of an intersection.
200323-210224 / Dror To do.
200321-161801 / Dror Debugging UOFix.nb and CountVPB.nb (2).
200321-161800 / Dror Debugging UOFix.nb and CountVPB.nb.
200320-161700 / Afeke Kassel-Turaev Section 3.2.1 (2).
200320-155143 / Afeke Kassel-Turaev Section 3.2.1.
200319-194117 / VanDerVeen UOFix.nb conventions.
200319-171019 / Frohlich Conversion between the BV trace and the H trace (2). (more...)
200319-171018 / Frohlich Conversion between the BV trace and the H trace.
200316-043626 / Dror UOFix conventions.
200313-012827 / Dror Failing slide moves (2).
200313-012826 / Dancso am, bm, swab; surgeries.
200312-190540 / VanDerVeen Misc.
200312-002719 / Dancso OU and lazy loops.
200311-203105 / Dror Failing slide moves.
Date-Time / Prefix Comment
200311-190547 / Afeke Reading Kirk's email (3).
200311-190226 / Afeke Reading Kirk's email.
200311-190225 / Afeke Reading Kirk's email (2).
200310-182912 / Frohlich The relation between DoPeGDO and $\Gamma$.
200310-182911 / Frohlich Linking numbers and traces.
200306-002621 / Dancso OU and Enriquez.
200305-175134 / Afeke Poincare Duality (2).
200305-170258 / Frohlich Setting up the trace equations.
200304-165010 / Gaudreau An issue with braid parities.
200303-175834 / VanDerVeen Smallness.
200303-165933 / Afeke Poincare Duality.
200302-222448 / Dancso Degree by degree twisting.
200302-015418 / Dancso The Enriquez universal space.
200226-131424 / Afeke Supervisory meeting.
200226-121732 / Frohlich Supervisory meeting.
200225-125253 / Gaudreau Supervisory meeting.
200219-123606 / Fresse Quantization of Poisson algebras (2).
200219-122454 / Fresse Quantization of Poisson algebras.
200219-114438 / Fresse Associated graded and cohomology.
200218-140232 / Ens Extending degree by degree (2).
200218-133719 / Ens Extending degree by degree.
200218-122812 / Fresse Braidors and associators (2).
200218-112646 / Fresse Braidors and associators.
200217-151739 / Afeke Poincare duality (6).
200217-145718 / Afeke Poincare duality (5).
200217-143014 / Stein Gauss diagram invariants for links.
200216-120117 / Gaudreau Slits and slides.
200211-131421 / Afeke Poincare duality (4).
200211-131325 / Afeke Poincare duality (3).
200211-131236 / Afeke Poincare duality (2).
200211-131200 / Afeke Poincare duality.
200211-130942 / Afeke Compositions in homological representations.
Date-Time / Prefix Comment
200211-120341 / Frohlich Co-invariants and traces (2).
200206-092914 / VanDerVeen $DPG_n$.
200205-142821 / Frohlich Co-invariants and traces.
200205-091751 / VanDerVeen Affine Lie algebras.
200205-075527 / VanDerVeen R2b, R2c, and (left-)(right-)(full-) Hopf algebras.
200204-121538 / Afeke Computing the braid action.
200128-213110 / Frohlich Finding the $PR^4$ syzygies (3).
200128-131445 / Afeke A basis for $H^1(X_0,p;F)$ (7).
200128-105755 / VanDerVeen Towards a Seifert formula.
200127-113252 / Frohlich Finding the $PR^4$ syzygies (2).
200127-105531 / Schaveling Inverting perturbatively, the dihedral symmetry group.
200122-130202 / Afeke A basis for $H^1(X_0,p;F)$ (6).
200122-125435 / Afeke A basis for $H^1(X_0,p;F)$ (5).
200122-123958 / Afeke A basis for $H^1(X_0,p;F)$ (4).
200122-115708 / Frohlich Finding the $PR^4$ syzygies.
200122-115707 / Frohlich Computing $PR^4$ homology.
200122-081653 / VanDerVeen The automorphism group of $gl_{n+}^\epsilon$.
200116-163137 / VanDerVeen A representation of $sl_{2+}^\epsilon$.
200116-163136 / VanDerVeen The cyclic structure of $gl_{n+}^\epsilon$.
200115-110130 / VanDerVeen The general form of a Seifert formula.
200114-100500 / Schaveling Quantizing $sl_n$ (3).
200114-100455 / Schaveling Quantizing $sl_n$ (2).
200114-100447 / Schaveling Quantizing $sl_n$.
200114-100437 / Schaveling $sl_3$ computations (6).
200114-100427 / Schaveling $sl_3$ computations (5).
200114-100420 / Schaveling $sl_3$ computations (4).
200113-095920 / Afeke A basis for $H^1(X_0,p;F)$ (3).
200113-095732 / Afeke A basis for $H^1(X_0,p;F)$ (2).
200113-094125 / Afeke A basis for $H^1(X_0,p;F)$.
200113-080502 / Dror Gropes and doubles.
200113-045334 / VanDerVeen The $\infty D$ DD theorem (2).
200110-120232 / VanDerVeen The $\infty D$ DD theorem.

See All Shots.