Last updated August 2009 by ingerbo[at]

Welcome to the seminarpage for autumn 2009

    The Algebra and Algebraic geometry group

Department of Mathematics, University of Oslo

General information about our mailing list algebra-seminar[at] can be found here.
Seminar history: Spring 2003, Autumn 2003, Spring 2004, Autumn 2004, Spring 2005, Autumn 2005, Spring 2006, Autumn 2006, Spring 2007, Autumn 2007, Spring 2008, Autumn 2008, Spring 2009
Fridays (when there is no Department Colloquium) 14.15, B70, Seminar i klassifikasjon av glatte projektive flater. Contact: Kristian Ranestad (ranestad).

Fridays 14.00 for 14.30, pausearealet 7. etasje, Felleskollokviet (Department Colloquium). Contact: Bjørn Jahren (bjoernj).

Seminar in Algebra and Algebraic geometry

Time: Mondays 14.15 (lunch at 11.45, 6. floor)
Venue: Seminar room B63, Niels Henrik Abel building
Organiser: Arne B. Sletsjøe (arnebs)

NB!     Next seminar:

31. August Algebra lunch and planning session
7. September Jan Christophersen (Oslo)
Ekvivelære trianguliseringer av torusen og abelske flater I
14. September Kristian Ranestad (Oslo)
En geometrisk karakterisering av Hankel-underrom
Hvis r < d så definerer radene i (r x d)-matrisa (a_i,j) der a_i,j=a_i-j et underrom av P^(d-1). Ved hjelp av apolaritet og projeksjoner av en rasjonal normal kurve vil jeg karakterisere disse underrommene.
21. September Lunch
28. September Lunch The Geometry seminar
5. October Jan Christophersen (Oslo)
Ekvivelære trianguliseringer av torusen og abelske flater II
12. October Michal Kapustka (Krakow/Oslo)
Unprojections and Mukai varieties
Mukai varieties M_g are key varieties for the description of canonical embeddings of curves of genus g<11. I shall present them using equations and use this presentation to prove that the projection of a general nodal linear section of the variety M_g is a linear section of M_{g-1}. This may be used to construct cascades of K3 surfaces, Fano and Calabi-Yau threefolds, and give a description of some Moduli spaces of bundles on them.
19. October Lunch
26. October Nelly Villamizar (Oslo)
Edwards coordinates for elliptic curves
Every elliptic curve over a field of characteristic different from 2 is birationally equivalent to a curve in Edwards form x^2+y^2=1+dx^2y^2. Some elliptic curves require a field extension for the transformation, but in many cases the transformations are defined over the original field. One reason for the great interest in Edwards curves is that the Edwards addition law is strongly unified: it applies to doubling points as well as to general addition, unlike the usual Weierstrass addition law. Strongly unified addition formulas had previously been published but the Edwards formulas are considerably faster. I have been studying the Edwards form from a more geometric point of view and that is what I will present in the talk.
2. November Lunch
9. November Lunch
12.-13. November Nasjonalt algebramøte
16. November Lunch
18. November NB! Venue: Høgskolen i Oslo, Pilestredet 35. Time: 12.30 (lunch 11.30, 9. floor)
Uwe Nagel (Kentucky)
Results and open problems in liaison theory
Liaison theory originated from the idea to study a curve by relating it to a simpler curve. Nowadays it may be considered as a classification theory for curves, surfaces, etc. In the talk we will introduce the basic concepts, discuss some classical and recent results, and conclude the description of the state of the art by describing some open problems.
23. November Lunch
30. November Lunch
7. December Jan Christophersen (Oslo)
Milnor fibere til sykliske kvosient singulariteter og fylte linserom
14. December Lutefisk-seminar
13.15-14.15: Gregory G. Smith (Queen's University)
Tangential schemes of determinantal varieties
The n-th jet scheme of a variety encodes the n-th order Taylor expansions of functions on the variety. The jet schemes associated to the varieties of matrices of a given rank are cut out by a relatively simple and explicit collection of polynomials. In this talk, I give an overview of the geometric properties of these jet schemes. I will also describe the minimal free resolution for the coordinate ring of some 1-st jet schemes.

14.30-15.15: Ulf Persson (Chalmers)
Familjer av trianglar med given inskriven och omskriven radie. Ett specialfall av Poncelet.

19.30: Lutefisk at Rorbua, Aker Brygge.