Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options questions only not deleted user 108274

Complex geometry is the study of complex manifolds, complex algebraic varieties, complex analytic spaces, and, by extension, of almost complex structures. It is a part of differential geometry, algebraic geometry and analytic geometry.

5 votes
0 answers
1k views

Saturated ideals in computational algebra

Let $R$ a commutative ring with one and $I, J \triangleleft R$ two ideals. The saturated ideal $I^{sat}_J$ with respect $J$ is the ideal $$(I : J^\infty )= \cup_{n \geq 1} (I:J^n)$$ where $(I:J^n)= \ …
user267839's user avatar
  • 5,966
3 votes
0 answers
346 views

When are two complex Tori biholomorphic

Let $g \ge 1$ be a natural number and $\mathbb{C}^g$ complex vector space which is isomorphic to $\mathbb{R}^{2g}$ is real vector space. An additive subgroup $\Gamma \subset \mathbb{C}^g$ is called a …
user267839's user avatar
  • 5,966
3 votes
0 answers
220 views

Historical proof of Leschetz Hyperplane Theorem

I browse in Phillip Griffiths' Slides on historical development of Hodge-theory and these include a sketch of the original approach with Lefschetz used to study complex surfaces in his famous hypersur …
user267839's user avatar
  • 5,966
2 votes
0 answers
156 views

Construct Torsion element in $H^2(X,\mathbb{Z})$ with Ambrose–Singer theorem

Let $X$ be a Kahler manifold. Using the exponential sequence one obtains a homomorphism $c_1:H^1(X,\mathcal{O}_X^*)\rightarrow H^2(X,\mathbb{Z})$. This is associating to a holomorphic line bundle $L$ …
user267839's user avatar
  • 5,966
2 votes
0 answers
83 views

Holomorphic map proper after shrinking (Kollar's Lecture on Resolution of Singularities)

I'm reading Janos Kolloar's Lecture on Resolution of Singularities and have some problems to understand a detail in the proof of Thm. 1.5 on page 10: Thm 1.5 (Riemann) Let $F(x,y)$ be an irreducibl …
user267839's user avatar
  • 5,966
2 votes
0 answers
522 views

Polarizations in algebraic and symplectic geometry

In context of Abelian varieties there are a couple of equivalent ways to introduce the polarization of a algebraic variety. One way is to choose a line bundle $\mathcal{L}$ which satisfies certain ide …
user267839's user avatar
  • 5,966
2 votes
1 answer
133 views

Generically finite projection $\pi_L: X \to \mathbb{P}^2$ from plane $L$ and critical points

(In following we are working in "classical" complex setting: i.e. all involved schemes are considered to be varieties over $k=\mathbb{C}$) Let $X \subset \mathbb{P}^n$ be irreducible surface and $L $ …
user267839's user avatar
  • 5,966
2 votes
1 answer
350 views

Comparison of classical and Zariski topologies with constructible sets

In David Mumford's book Algebraic Geometry I, Complex Projective Varieties the proof of (3.25) Specialization principle on page 53 contains an argument I not understand. General assumptions: all our v …
user267839's user avatar
  • 5,966
2 votes
1 answer
594 views

Example motivating mixed Hodge structures

The suggested intuition behind mixed Hodge structures - developed in particular to generalize Hodge decomposition of cohomology groups from complex smooth complete varieties to more general algebraic …
user267839's user avatar
  • 5,966
2 votes
1 answer
212 views

Prefactor $2\pi i$ for Tate-Hodge structure

A rather basic question. What was the original reason to consider the underlying $\mathbb{Z}$-module of the - as canonical object regarded - Tate-Hodge structure $\mathbb{Z}(1)$ to be given as $2 \pi …
user267839's user avatar
  • 5,966
2 votes
0 answers
1k views

Explicit construction of Fubini Study Metric

I have a question about a remark on Fubini Study metric on $\mathbb{CP}^n$ from Notes on canonical Kähler metrics on page 8 is remarked (Example 2.12 4.): Fix a Hermitian innerproduct on $\mathbb{C}^ …
user267839's user avatar
  • 5,966
2 votes
0 answers
164 views

Principle of degeneration as precursor of Zariski's connectedness theorem (geometric intuition)

I have following question about so-called "principle of degeneration" in algebraic geometry (which in modern terms is an immediate consequence of Zariski's main theorem and goes in it's original form …
user267839's user avatar
  • 5,966
2 votes
0 answers
183 views

Zariski Connectedness Theorem in Complex Geometry

Let $f: X \to Y$ be a proper surjective morphism of complex irreducible varieties such that general fibre of $f$ is connected and $Y$ integrally closed\normal. Say, we even assume wlog $Y=\text{Spec}( …
user267839's user avatar
  • 5,966
2 votes
0 answers
149 views

Zariski Connectedness Theorem: From Analytic & Topological Viewpoint

Let $p:Y \to X$ be a proper, flat (see later why) surjective map between smooth connected complex varieties $Y,X$, esp. $X$ unibranch. Assume that there exist a Zariski open (esp. dense) $U \subset X$ …
user267839's user avatar
  • 5,966
1 vote
0 answers
693 views

Questions on Néron–Severi group

$\DeclareMathOperator\NS{NS}\DeclareMathOperator\Pic{Pic}$I have two questions on a comment from Daniel Hyubrechts's Complex Geometry on pages 133/134. Let $X$ be a compact Kähler manifold. Consider …
user267839's user avatar
  • 5,966

15 30 50 per page