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Speaker:

Masha Vlasenko
Affiliation:

MPIM
Date:

Wed, 02/06/2010 - 15:00 - 16:00
Location:

MPIM Lecture Hall
Parent event:

Number theory lunch seminar We consider certain $r$-fold $q$-hypergeometric series depending on several rational parameters. These series arise in conformal field theory and it is of interest to know for which values of parameters they are modular. A conjectural (partial) answer by Werner Nahm surprisingly involves dilogarithms and the Bloch group. This conjecture was proved by Don Zagier for rank $r=1$ and also tested numerically by him and Michael Terhoeven for higher ranks $r>1$. We develop a general method of finding values of parameters corresponding to modular cases and apply it for $r=1$ (reproving Zagier's result) and $r=2$ (obtaining several modular cases not known earlier).

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