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Mathematician, researching in Algebraic Geometry and related topics.
18h

comment 
The name for the quotient property
What is (if any) the relation of (???) with the usual concept of open map? I mean, continuity + (???) imply that $f$ is open? 
2d

awarded  Enlightened 
2d

comment 
College  Ecuation to solve in 3 variables (p,q,r) in [1,2]
1) MO is not for homework. 2) Even if MO were for homework, the effort to write "equation" correctly would be appreciated. Voted to close. 
2d

awarded  Nice Answer 
2d

revised 
Extending holomorphic functions
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Oct 17 
revised 
Holomorphic Line Bundles over a Homogeneous Space
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Oct 17 
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Euler characteristic of open varieties as degree of Chern class of logarithmic differentials
You are welcome. Well, in the other few books that I checked, I did not find the explicit computation of $\chi(U)$ in terms of $c_n$ of the logarithmic (co)tangent bundle. I think that the original computation is due to Deligne (maybe Theorie de Hodge II?), you should try and look there. 
Oct 17 
answered  Euler characteristic of open varieties as degree of Chern class of logarithmic differentials 
Oct 14 
comment 
Theorem on the algebraic manipulation of divergent series
en.wikipedia.org/wiki/Riemann_series_theorem 
Oct 10 
revised 
Holomorphic Line Bundles over a Homogeneous Space
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Oct 10 
answered  Holomorphic Line Bundles over a Homogeneous Space 
Oct 10 
revised 
Does one real radical root imply they all are?
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Oct 10 
revised 
Number of minimal models of a surface
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Oct 10 
revised 
Number of minimal models of a surface
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Oct 10 
revised 
Number of minimal models of a surface
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Oct 9 
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Line on a hyper surface
Think about the first case, that is $n=3$. By NoetherLefschetz theorem, the very general surface $X$ of degree $\geq 5$ in $\mathbb{P}^3$ has the Picard group which is generated by the hyperplane section. In particular, $X$ contains no lines (more generally, no smooth rational curves). 
Oct 9 
revised 
Number of minimal models of a surface
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Oct 9 
comment 
Number of minimal models of a surface
Of course: they are all minimal models belonging to the the birational equivalence class of the ruled surface $C \times \mathbb{P}^1$. 
Oct 9 
revised 
Number of minimal models of a surface
added 64 characters in body 
Oct 9 
answered  Number of minimal models of a surface 