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The Pandharipande-Thomas rationality conjecture for superpositive curve classes on projective complex 3-manifolds

Algebraic Geometry 2026-04-08 v1

Abstract

Let XX be a projective complex 3-manifold. An effective curve class βH2(X,Z)\beta\in H_2(X,\mathbb Z) is called positive if c1(X)β>0c_1(X)\cdot\beta>0, and superpositive if all the effective summands of β\beta are positive. If XX is Fano then all curve classes are superpositive. In arXiv:2111.04694 the second author developed a theory of enumerative invariants in abelian categories and wall-crossing formulae. We use this theory to prove conjectures by Pandharipande and Thomas on the rationality and poles of generating functions of Pandharipande-Thomas invariants of XX with descendent insertions, for superpositive curve classes.

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Cite

@article{arxiv.2604.05664,
  title  = {The Pandharipande-Thomas rationality conjecture for superpositive curve classes on projective complex 3-manifolds},
  author = {Reginald Anderson and Dominic Joyce},
  journal= {arXiv preprint arXiv:2604.05664},
  year   = {2026}
}

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38 pages