Knot at Lunch on January 30 2008: Difference between revisions

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** Is there an Artin's theorem for pure virtual braids?
** Is there an Artin's theorem for pure virtual braids?
** What is the finite type completion of <math>\operatorname{Aut}(F_n)</math>? How about some of its obvious subgroups?
** What is the finite type completion of <math>\operatorname{Aut}(F_n)</math>? How about some of its obvious subgroups?

* Infinitesimal Artin - derivations on free Lie algebras.
** Derivations, tangential derivations, special derivations (see {{BBS Link|Alekseev-080116-162451.jpg}}).
** Drinfel'd's theorem on special derivations (see Drinfel'd's ''On quasitriangular Quasi-Hopf algebras and a group closely connected with <math>\operatorname{Gal}(\bar{{\Bbb Q}}/{\Bbb Q})</math>'', Leningrad Math. J. '''2''' (1991) 829-860, though I wouldn't be surprised if the theorem is actually older).
** Can you prove that <math>{\mathcal A}^\mbox{hor}</math> injects into <math>{\mathcal A}^\mbox{trees}</math>?
** The VS structure on several kinds of algebras of derivations. As always, can you find associators?
** The Alekseev-Torossian "divergence" ({{BBS Link|Alekseev-080121-093327.jpg}}).

Latest revision as of 11:33, 4 February 2008

Invitation

Dear Knot at Lunch People,

We will have our next lunch on Wednesday January 30, at the usual place, Bahen 6180, at 12 noon.

As always, please bring brown-bag lunch and fresh ideas. The agenda: we may talk a bit about Artin's theorem on the braid group and automorphisms of the free group, or we may talk about something else.

Further information about this meeting will/may appear at https://drorbn.net/drorbn/index.php?title=Knot_at_Lunch_on_January_30_2008.

As always, if you know anyone I should add to this mailing list or if you wish to be removed from this mailing list please let me know. To prevent junk accumulation in mailboxes, I will actively remove inactive people unless they request otherwise.

Best,

Dror.

Another Invitation

Madre, at Aluna Theatre, January 29 - February 17, featuring Hernando's daughter Juliette Burgos.

Possible Agenda

  • The Artin representation of the pure braid group on strand into the automorphism group of the free group on generators (hey, I'm not even sure that's what it's called!).
    • Abstract definition.
    • Practical computation from the Wirtinger presentation.
    • Practical computation by stirring the soup.
    • Properties.
    • Artin's theorem (is that what it's called?).
    • Is there an Artin's theorem for pure virtual braids?
    • What is the finite type completion of ? How about some of its obvious subgroups?