On the imaginary simple roots of the Borcherds algebra g-II(9,1)

May, 1997
10 pages
Published in:
  • Nucl.Phys.B 510 (1998) 721-738
e-Print:
Report number:
  • IASSNS-HEP-97-53,
  • AEI-037

Citations per year

200220052008201120132310
Abstract:
In a recent paper (hep-th/9703084) it was conjectured that the imaginary simple roots of the Borcherds algebra gII9,1g_{II_{9,1}} at level 1 are its only ones. We here propose an independent test of this conjecture, establishing its validity for all roots of norm 8\geq -8. However, the conjecture fails for roots of norm -10 and beyond, as we show by computing the simple multiplicities down to norm -24, which turn out to be remakably small in comparison with the corresponding E10E_{10} multiplicities. Our derivation is based on a modified denominator formula combining the denominator formulas for E10E_{10} and gII9,1g_{II_{9,1}}, and provides an efficient method for determining the imaginary simple roots. In addition, we compute the E10E_{10} multiplicities of all roots up to height 231, including levels up to =6\ell =6 and norms -42.
  • 11.25.H
  • 02.10.S
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  • algebra: Kac-Moody
  • algebra: E(10)
  • algebra: representation
  • analytic properties