ABSTRACT. We derive and study a quantum group g p,q that is Kazhdan-Lusztig-dual to the W -algebra W p,q of the logarithmic (p, q) conformal field theory model. The algebra W p,q is generated by two currents W + (z) and W − (z) of dimension (2p−1)(2q−1), and the energy-momentum tensor T (z). The two currents generate a vertex-operator ideal R with the property that the quotient W p,q /R is the vertex-operator algebra of the (p, q) Virasoro minimal model. The number (2pq) of irreducible g p,q representations is the same as the number of irreducible W p,q -representations on which R acts nontrivially. We find the center of g p,q and show that the modular group representation on it is equivalent to the modular group representation on the W p,q characters and "pseudocharacters." The factorization of the g p,q ribbon element leads to a factorization of the modular group representation on the center. We also find the g p,q Grothendieck ring, which is presumably the "logarithmic" fusion of the (p, q) model.
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