2005/06/28 by Alexander Polishchuk, Polishchuk, Alexander
Mathematics · Physics and Astronomy · #Advanced Topics in Algebra #Algebraic Geometry (math.AG) #Algebraic structures and combinatorial models #FOS: Mathematics #Nonlinear Waves and Solitons #Quantum Algebra (math.QA) #math.AG #math.QA
paper · pdf · doi:10.48550/arxiv.math/0506571
34 pages, a new result on the equivalence of derived categories is added, exposition improved
openalex publication_date 2005/06/28 · arxiv created 2006/06/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We introduce the notion of a quasicoherent sheaf on a complex noncommutative two-torus T as an ind-object in the category of holomorphic vector bundles on T. Extending the results of math.QA/0211262 and math.QA/0308136 we prove that the derived category of quasicoherent sheaves on T is equivalent to the derived category of usual quasicoherent sheaves on the corresponding elliptic curve. We define the rank of a quasicoherent sheaf that can take arbitrary nonnegative real values. We study the category \Qcoh(ηT) obtained by taking the quotient of the category of quasicoherent sheaves by the subcategory of objects of rank zero (called torsion sheaves). We show that projective objects of finite rank in \Qcoh(ηT) are classified up to an isomorphism by their rank. We also prove that the subcategory of objects of finite rank in \Qcoh(ηT) is equivalent to the category of finitely presented modules over a semihereditary algebra.