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Loop groups and twisted \(K\)-theory. III. (English) Zbl 1239.19002

Summary: For part I see [the authors, J. Topol. 4, No. 4, 737–798 (2011; Zbl 1241.19002)].
In this paper, we identify the Ad-equivariant twisted \(K\)-theory of a compact Lie group \(G\) with the “Verlinde group” of isomorphism classes of admissible representations of its loop groups. Our identification preserves natural module structures over the representation ring \(R(G)\) and a natural duality pairing. Two earlier papers in the series covered foundations of twisted equivariant \(K\)-theory, introduced distinguished families of Dirac operators and discussed the special case of connected groups with free \(\pi_1\). Here, we recall the earlier material as needed to make the paper self-contained. Going further, we discuss the relation to semi-infinite cohomology, the fusion product of conformal field theory, the rôle of energy and a topological Peter-Weyl theorem.

MSC:

19L50 Twisted \(K\)-theory; differential \(K\)-theory
19L47 Equivariant \(K\)-theory
22E67 Loop groups and related constructions, group-theoretic treatment
81T45 Topological field theories in quantum mechanics

Citations:

Zbl 1241.19002
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[1] M. F. Atiyah and I. M. Singer, ”Index theory for skew-adjoint Fredholm operators,” Inst. Hautes Études Sci. Publ. Math., iss. 37, pp. 5-26, 1969. · Zbl 0194.55503
[2] M. F. Atiyah, R. Bott, and A. Shapiro, ”Clifford modules,” Topology, vol. 3, iss. suppl. 1, pp. 3-38, 1964. · Zbl 0146.19001
[3] M. F. Atiyah, V. K. Patodi, and I. M. Singer, ”Spectral asymmetry and Riemannian geometry. I,” Math. Proc. Cambridge Philos. Soc., vol. 77, pp. 43-69, 1975. · Zbl 0297.58008
[4] B. Blackadar, \(K\)-Theory for Operator Algebras, New York: Springer-Verlag, 1986, vol. 5. · Zbl 0597.46072
[5] A. Borel, ”Sous-groupes commutatifs et torsion des groupes de Lie compacts connexes,” Tôhoku Math. J., vol. 13, pp. 216-240, 1961. · Zbl 0109.26101
[6] R. Bott, ”Homogeneous vector bundles,” Ann. of Math., vol. 66, pp. 203-248, 1957. · Zbl 0094.35701
[7] T. Bröcker and T. tom Dieck, Representations of Compact Lie Groups, New York: Springer-Verlag, 1995, vol. 98. · Zbl 0874.22001
[8] U. Bunke and I. Schröder, ”Twisted \(K\)-theory and TQFT,” in Mathematisches Institut, Georg-August-Universität Göttingen: Seminars Winter Term 2004/2005, Universitätsdrucke Göttingen, Göttingen, 2005, pp. 33-80. · Zbl 1162.19300
[9] D. S. Freed, ”The Verlinde algebra is twisted equivariant \(K\)-theory,” Turkish J. Math., vol. 25, iss. 1, pp. 159-167, 2001. · Zbl 0971.55006
[10] D. S. Freed, ”Twisted \(K\)-theory and loop groups,” in Proceedings of the International Congress of Mathematicians, Vol. III, Beijing, 2002, pp. 419-430. · Zbl 0997.19004
[11] B. L. Feuigin and E. V. Frenkel, ”Affine Kac-Moody algebras and semi-infinite flag manifolds,” Comm. Math. Phys., vol. 128, iss. 1, pp. 161-189, 1990. · Zbl 0722.17019
[12] I. B. Frenkel, H. Garland, and G. J. Zuckerman, ”Semi-infinite cohomology and string theory,” Proc. Nat. Acad. Sci. U.S.A., vol. 83, iss. 22, pp. 8442-8446, 1986. · Zbl 0607.17007
[13] D. S. Freed, M. J. Hopkins, and C. Teleman, Loop groups and twisted \(K\)-theory I. · Zbl 1241.19002
[14] D. S. Freed, M. J. Hopkins, and C. Teleman, Loop groups and twisted \(K\)-theory II. · Zbl 1273.22015
[15] D. S. Freed, M. J. Hopkins, and C. Teleman, ”Twisted equivariant \(K\)-theory with complex coefficients,” J. Topol., vol. 1, iss. 1, pp. 16-44, 2008. · Zbl 1188.19005
[16] D. S. Freed, M. J. Hopkins, and C. Teleman, ”Consistent orientation of moduli spaces,” in The Many Facets of Geometry, Oxford: Oxford Univ. Press, 2010, pp. 395-419. · Zbl 1257.19004
[17] H. Garland and J. Lepowsky, ”Lie algebra homology and the Macdonald-Kac formulas,” Invent. Math., vol. 34, iss. 1, pp. 37-76, 1976. · Zbl 0358.17015
[18] V. Guillemin and S. Sternberg, ”Geometric quantization and multiplicities of group representations,” Invent. Math., vol. 67, iss. 3, pp. 515-538, 1982. · Zbl 0503.58018
[19] V. G. Kac, Infinite-Dimensional Lie Algebras, Third ed., Cambridge: Cambridge Univ. Press, 1990. · Zbl 0716.17022
[20] B. Kostant, ”A cubic Dirac operator and the emergence of Euler number multiplets of representations for equal rank subgroups,” Duke Math. J., vol. 100, iss. 3, pp. 447-501, 1999. · Zbl 0952.17005
[21] B. Kostant, ”A generalization of the Bott-Borel-Weil theorem and Euler number multiplets of representations. Conference Moshé Flato 1999 (Dijon),” Lett. Math. Phys., vol. 52, iss. 1, pp. 61-78, 2000. · Zbl 0960.22011
[22] B. Kostant and S. Sternberg, ”Symplectic reduction, BRS cohomology, and infinite-dimensional Clifford algebras,” Ann. Physics, vol. 176, iss. 1, pp. 49-113, 1987. · Zbl 0642.17003
[23] S. Kumar, ”Demazure character formula in arbitrary Kac-Moody setting,” Invent. Math., vol. 89, iss. 2, pp. 395-423, 1987. · Zbl 0635.14023
[24] G. D. Landweber, ”Multiplets of representations and Kostant’s Dirac operator for equal rank loop groups,” Duke Math. J., vol. 110, iss. 1, pp. 121-160, 2001. · Zbl 1018.17016
[25] B. H. Lawson Jr. and M. Michelsohn, Spin Seometry, Princeton, NJ: Princeton Univ. Press, 1989, vol. 38. · Zbl 0688.57001
[26] J. Mickelsson, ”Gerbes, (twisted) \(K\)-theory, and the supersymmetric WZW model,” in Infinite Dimensional Groups and Manifolds, Berlin: de Gruyter, 2004, vol. 5, pp. 93-107. · Zbl 1058.81067
[27] O. Mathieu, ”Formules de caractères pour les algèbres de Kac-Moody générales,” in Astérisque, , 1988, vol. 159-160, p. 267. · Zbl 0683.17010
[28] A. Pressley and G. Segal, Loop Groups, New York: The Clarendon Press Oxford Univ. Press, 1986. · Zbl 0618.22011
[29] G. Segal, ”The representation ring of a compact Lie group,” Inst. Hautes Études Sci. Publ. Math., iss. 34, pp. 113-128, 1968. · Zbl 0209.06203
[30] C. H. Taubes, Notes on the Dirac operator on loop space, 1989.
[31] C. Teleman, ”Borel-Weil-Bott theory on the moduli stack of \(G\)-bundles over a curve,” Invent. Math., vol. 134, iss. 1, pp. 1-57, 1998. · Zbl 0980.14025
[32] C. Teleman, ”\(K\)-theory of the moduli of principal bundles on a surface and deformations of the Verlinde algebra,” in Proceedings of the 2002 Oxford Symposium in Honour of the 60th Birthday of Graeme Segal, CUP, 2004. · Zbl 1123.53048
[33] V. Toledano Laredo, ”Positive energy representations of the loop groups of non-simply connected Lie groups,” Comm. Math. Phys., vol. 207, iss. 2, pp. 307-339, 1999. · Zbl 0969.22010
[34] R. Wendt, ”A character formula for representations of loop groups based on non-simply connected Lie groups,” Math. Z., vol. 247, iss. 3, pp. 549-580, 2004. · Zbl 1063.22022
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