Abstract
Branch points of a real 2-surface Σ in a 4-manifold M generalize branch points of complex curves in complex surfaces: for example, they can occur as singularities of minimal surfaces. We investigate such a branch point p when Σ is topologically embedded. It defines a link L(p), the components of which are closed braids with the same axis up to orientation. If Σ is closed without boundary, the contribution of p to the degree of the normal bundle of Σ in M can be computed on the link L(p), in terms of the algebraic crossing numbers of its components and of their linking numbers with one another.
Similar content being viewed by others
References
Bennequin D.: Entrelacements et équations de Pfaff, Third Schnepfenried Geometry Conference, vol. 1 (Schnepfenried 1982), 87–161, Astérisque 107–108, Soc. Math. France, Paris (1983)
Birman J., Wrinkle N.: On transversally simple knots. J. Diff. Geom. 55(2), 325–353 (2000)
Eells J., Salamon S.: Twistorial constructions of harmonic maps of surfaces in 4-manifolds. Ann. Scuola Norm. di Pisa 12, 589–640 (1985)
Gauduchon P.: Pseudo-immersions superminimales d’une surface de Riemann dans une variété riemannienne de dimension 4. Bull. Soc. Math. France 114, 447–508 (1986)
Griffiths P., Harris J.: Principles of Algebraic Geometry. Wiley, New York (1978)
Gulliver R.D., Osserman R., Royden H.L.: A theory of branched immersions of surfaces. Am. J. Math. 95, 750–812 (1973)
Micallef M., White B.: The structure of branch points in minimal surfaces and in pseudo-holomorphic curves. Ann. Math. 141, 35–85 (1995)
Milnor J.: Singular Points of Complex Hypersurfaces. PUP, Princeton (1968)
Ville, M.: On the normal bundle of minimal surfaces in almost Kähler manifolds. In: Anand C.K., Baird P., Loubeau E., Wood J.C. (eds.) Harmonic morphisms, harmonic maps and related topics. Pitman Res. Notes in Maths, Brest 1997 (1999)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ville, M. Branched immersions and braids. Geom Dedicata 140, 145–162 (2009). https://doi.org/10.1007/s10711-008-9313-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10711-008-9313-6
Keywords
- Surfaces in 4-manifolds
- Branch points
- Characteristic numbers
- Braids
- Transverse knots
- Twistors
- Minimal surfaces