An effective criterion for algebraicity of rational normal surfaces

TL;DR

This paper introduces a new effective criterion to determine when rational normal analytic surfaces are algebraic, based on resolving singularities and contracting divisors, and constructs examples of non-algebraic surfaces close to being algebraic.

Contribution

It provides a novel criterion for algebraicity of rational normal surfaces and constructs new classes of non-algebraic surfaces near the algebraic boundary.

Findings

New criterion for algebraicity of rational normal surfaces

Construction of non-algebraic surfaces close to algebraic ones

Reformulation and proof of Mondal's correspondence theorem

Abstract

We give a novel and effective criterion for algebraicity of rational normal analytic surfaces constructed from resolving the singularity of an irreducible curve-germ on $CP^2$ and contracting the strict transform of a given line and all but the `last' of the exceptional divisors. As a by-product we construct a new class of analytic non-algebraic rational normal surfaces which are `very close' to being algebraic. These results are local reformulations of some results in (Mondal, 2011) which sets up a correspondence between normal algebraic compactifications of $C^2$ with one irreducible curve at infinity and algebraic curves in $C^2$ with one place at infinity. This article is meant partly to be an exposition to (Mondal, 2011) and we give a proof of the correspondence theorem of (Mondal, 2011) in the `first non-trivial case'.