nLab elliptic fibration



Elliptic cohomology





An elliptic fibration is a bundle of elliptic curves, possibly including some singular fibers.

An elliptic surface is an elliptic fibration over an algebraic curve.


Classification by local systems with modular group coefficients

Write SL 2()SL_2(\mathbb{Z}) for the special linear group in dimension 2 with integer coefficients and write SL 2()PSL 2()SL_2(\mathbb{Z}) \to PSL_2(\mathbb{Z}) for the projection to the corresponding projective linear group. Regarding this as the Möbius group it comes with its natural action on the upper half plane 𝔥\mathfrak{h}. The homotopy quotient ell()=𝔥//SL 2()\mathcal{M}_{ell}(\mathbb{C}) = \mathfrak{h}//SL_2(\mathbb{Z}) is the moduli stack of elliptic curves over the complex numbers.

Accordingly, to any SL 2()SL_2(\mathbb{Z})-principal bundle PBP \to B (necessarily flat since SL 2()SL_2(\mathbb{Z}) is a discrete group, hence a “local system”) is associated a 𝔥\mathfrak{h}-fiber bundle such that a section of it defines a non-singular elliptic fibration.

One may turn this around: Given an elliptic fibration EBE \to B, then away from the points SBS\subset B over which the fiber is singular, it is given by an SL 2()SL_2(\mathbb{Z})-local system together with a section of the associated upper-half plane bundle on BSB-S.

With due technical care, this data uniquely characterizes the elliptic fibration (e.g. Miranda 88, prop. VI.3.3).

Classification of the singular fibers

The remaining singular fibers follow an ADE classification (Kodaira 64, Néron 64, Kodaira 66)


Elliptic fibration of K3-surfaces

See at elliptic fibration of a K3-surface.


Specifically for complex surfaces:

See also:

Specifically for elliptically fibered K3-surfaces:

The ADE classification of the possible singular fibers is due to

  • Kunihiko Kodaira, (1964). “On the structure of compact complex analytic surfaces. I”. Am. J. Math. 86: 751–798. doi:10.2307/2373157. Zbl 0137.17501.

  • Kunihiko Kodaira, (1966). “On the structure of compact complex analytic surfaces. II”. Am. J. Math. 88: 682–721. doi:10.2307/2373150. Zbl 0193.37701.


  • André Néron, (1964). “Modeles minimaux des variétés abeliennes sur les corps locaux et globaux”. Publications Mathématiques de l’IHÉS (in French) 21: 5–128.

Last revised on March 1, 2023 at 05:58:08. See the history of this page for a list of all contributions to it.