Grothendieck decompostion simple example

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In summary, the conversation discusses the representation of exp{(\omega)} in terms of holomorphic and antiholomorphic functions F+ and F-. It is mentioned that if \omega has a simple pole, it can be represented by a Laurant series on the punctured disk. However, there is a problem with a missing factor of log on z. This is disproven by considering w=1/z, where exp(w) has an essential singularity at z=0. It is then stated that if F+ and F- are holomorphic and antiholomorphic, then exp(F+) and exp(F-) would be close to 1 near z=0, making |exp(F+)*exp(F-)/z| bounded
  • #1
Jim Kata
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Say you have [tex]exp{(\omega)}[/tex] and [tex]\omega[/tex] has a simple pole show that
[tex]exp{(\omega)}=exp{(F+)}z^{-1}exp{(F-)}[/tex] where F+ is holomorphic and F- is antiholomorphic. My basic thought is if [tex]\omega[/tex] has a simple pole then [tex]\omega z[/tex] is holomorphic and on the punctured disk it can be represented by a Laurant series. The problem is that I'm missing a factor of log on z.
 
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  • #2
That can't be right - consider w=1/z, so exp(w) has an essential singularity at z=0 and thus hits almost every value in a neighbourhood of 0. But if F+ and F- are holomorphic and antiholomorphic then exp(F+) and exp(F-) would be close to 1 near z=0, which means that |exp(F+)*exp(F-)/z| is bounded from below near z=0.
 

1. What is the Grothendieck decomposition simple example?

The Grothendieck decomposition is a theorem in algebraic geometry that states that any coherent sheaf on a projective variety can be decomposed into a direct sum of simpler sheaves. A simple example of this is the decomposition of a line bundle on a projective space into a direct sum of invertible sheaves.

2. Why is the Grothendieck decomposition important?

The Grothendieck decomposition is a powerful tool in algebraic geometry for understanding the structure of coherent sheaves on projective varieties. It allows for the reduction of complex sheaves into simpler components, making them easier to study and manipulate.

3. How is the Grothendieck decomposition proven?

The Grothendieck decomposition is proven using techniques from homological algebra and algebraic geometry. It relies on the existence of the Harder-Narasimhan filtration and the Grauert-Mülich theorem.

4. Can the Grothendieck decomposition be extended to non-projective varieties?

Yes, the Grothendieck decomposition has been extended to non-projective varieties, such as quasi-projective varieties. However, the decomposition may not always hold for general non-projective varieties.

5. How is the Grothendieck decomposition used in research?

The Grothendieck decomposition has many applications in algebraic geometry and related fields. It has been used in the study of moduli spaces, intersection theory, and the birational geometry of algebraic varieties. It also has connections to other areas of mathematics, such as representation theory and mathematical physics.

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