U (1)-invariant special Lagrangian 3-folds in $Bbb{C}^3$ and special Lagrangian fibrations

U (1)-invariant special Lagrangian 3-folds in $Bbb{C}^3$ and special Lagrangian fibrations

This is a survey of the author's series of three papers [8, 9, 10] on special Lagrangian 3-folds (SL 3-folds) in ${mathbb C}^3$ invariant under the U(1)-action ($z_1$, $z_2$, $z_3$)$mapsto$ ($e^itheta$ $z_1$, $e^-itheta$ $z_2$, $z_3$), and their sequel [11] on special Lagrangian fibrations and the SYZ Conjecture. We briefly present the main results of these four long papers, giving some explanation and motivation, but no proofs. The aim is to make the results and ideas accessible to String Theorists and others who have an interest in special Lagrangian 3-folds and fibrations, but have no desire to read pages of technical analysis. Let N be an SL 3-fold in ${mathbb C}^3$ invariant under the U(1)-action above. Then $|z_1|^2$ - $|z_2|^2$ = 2a on N for some a $in$ ${mathbb R}$. Locally, N can be written as a kind of graph of functions u,v: ${mathbb R}^2$ $rightarrow$ ${mathbb R}$ satisfying a nonlinear Cauchy--Riemann equation depending on a, so that u+iv is like a holomorphic function of x + iy. When a = 0 the equations may have singular points where u,v are not differentiable, which leads to analytic difficulties. We prove existence and uniqueness results for solutions u,v on domains S in ${mathbb R}^2$ with boundary conditions, including singular solutions. We study their singularities, giving a rough classification by multiplicity and type. We prove the existence of large families of fibrations of open subsets of ${mathbb C}^3$ by U(1)-invariant SL 3-folds, including singular fibres. Finally, we use these fibrations as local models to draw conclusions about the SYZ Conjecture on Mirror Symmetry of Calabi-Yau 3-folds.

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  • [1] M. Gross, Special Lagrangian fibrations I: Topology. In M.-H. Saito, Y. Shimizu, and K. Ueno, editors, Integrable Systems and Algebraic Geometry, pages 156-193, World Scientific, Singapore, 1998. alg-geom/9710006.
  • [2] M. Gross, Special Lagrangian fibrations II: Geometry. In Differential Geometry inspired by String Theory, Surveys in Differential Geometry 5, pages 341-403, International Press, 1999. math.AG/9809072.
  • [3] M. Gross, Topological mirror symmetry, Invent. math. 144 (2001), 75-137. math.AG/9909015.
  • [4] M. Gross, Examples of special Lagrangian fibrations. In K. Fukaya, Y.-G. Oh, K. Ono and G.Tian, editors, Symplectic geometry and mirror symmetry (Seoul, 2000), pages 81-109,World Scientific, Singapore, 2001. math.AG/0012002.
  • [5] R. Harvey and H.B. Lawson, Calibrated geometries, Acta Mathematica 148 (1982), 47-157.
  • [6] D.D. Joyce, Constructing special Lagrangian m-folds in Cm by evolving quadrics, Math. Ann. 320 (2001), 757-797. math.DG/0008155.
  • [7] D.D. Joyce, Lectures on Calabi-Yau and special Lagrangian geometry, math.DG/0108088,2001. Published, with added material, as Part I of M. Gross, D. Huybrechts and D. Joyce, Calabi-Yau Manifolds and Related Geometries, Universitext series, Springer, Berlin, 2003.
  • [8] D.D. Joyce, U(1)-invariant special Lagrangian 3-folds. I. Nonsingular solutions, math.DG/0111324, 2001. To appear in Advances in Mathematics.
  • [9] D.D. Joyce, U(1)-invariant special Lagrangian 3-folds. II. Existence of singular solutions, math.DG/0111326, 2001.
  • [10] D.D. Joyce, U(1)-invariant special Lagrangian 3-folds. III. Properties of singular solutions, math.DG/0204343, 2002.
  • [11] D.D. Joyce, Singularities of special Lagrangian fibrations and the SYZ Conjecture, math.DG/0011179. Version 2, 2002.
  • [12] W.-D. Ruan, Lagrangian tori fibration of toric Calabi-Yau manifold I, math.DG/9904012,1999.
  • [13] W.-D. Ruan, Lagrangian torus fibration and mirror symmetry of Calabi-Yau hypersurface in toric variety, math.DG/0007028, 2000.
  • [14] A. Strominger, S.-T. Yau, and E. Zaslow, Mirror symmetry is T-duality, Nuclear Physics B479 (1996), 243-259. hep-th/9606040.