University of Leeds

Department of Applied Mathematics and
Centre for Nonlinear Studies

Friday November 23rd, 2007
3.00 pm in LT11 of the Roger Stevens Building.


Victor M. Buchstaber
Manchester
e-mail: Victor.Buchstaber@manchester.ac.uk

Problem of differentiation of an Abelian function over its parameters.

The theory of Abelian functions was a central topic of the 19th century mathematics. In mid-seventies of the last century a new wave arose of investigation in this field in response to the discovery that Abelian functions provide solutions of a number of challenging problems of modern Theoretical and Mathematical Physics.

In a cycle of our joint papers with V. Enolskii and D. Leykin we have developed a theory of multivariate sigma-function, an analogue of the classic Weierstrass sigma-function.

A sigma-function is defined on a cover of U , where U is the space of a bundle p : U ! B defined by a family of plane algebraic curves of fixed genus. The base B of the bundle is the space of the family parameters and a fiber Jb over b 2 B is the Jacobi variety of the curve with the parameters b. A second logarithmic derivative of the sigma-function along the fiber is an Abelian function on Jb.

Thus, one can generate a ring F of fiber-wise Abelian functions on U. The problem to find derivations of the ring F along the base B is a reformulation of the classic problem of differentiation of Abelian functions over parameters. Its solution is relevant to a number of topical applications.

The talk presents a solution of this problem recently found by the speaker and D. Leykin.

References

  1. V.M.Buchstaber, D.V.Leykin, Addition laws on Jacobian varieties of plane algebraic curves, Proc. Steklov Math. Inst. 251 (2005), 49 120.
  2. V. M. Buchstaber, D. V. Leykin, Differentiation of Abelian functions over its parameters, Russian Math. Surveys, v. 62, Issue 4, 2007, 1.

Contact A.P. Fordy (email: allan@maths.leeds.ac.uk ) for further details.

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