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Nadel vanishing theorem

Nadel vanishing theorem is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Nadel vanishing theorem rather than just read about it. In short: In mathematics, the Nadel vanishing theorem is a global vanishing theorem for multiplier ideals, introduced by A. M.

Key takeaways

  • Nadel vanishing theorem belongs to mathematics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Nadel vanishing theorem to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Nadel vanishing theorem from memory before moving on to harder problems.

Reference excerpt

In mathematics, the Nadel vanishing theorem is a global vanishing theorem for multiplier ideals, introduced by A. M. Nadel in 1989. It generalizes the Kodaira vanishing theorem using singular metrics with (strictly) positive curvature, and also it can be seen as an analytical analogue of the Kawamata–Viehweg vanishing theorem.

Statement The theorem can be stated as follows. Let X be a smooth complex projective variety, D an effective Q {\displaystyle \mathbb {Q} } -divisor and L a line bundle on X, and J ( D ) {\displaystyle {\mathcal {J}}(D)} is a multiplier ideal sheaves. Assume that L − D {\displaystyle L-D} is big and nef. Then

H i ( X , O X ( K X + L ) ⊗ J ( D ) ) = 0 for i > 0. {\displaystyle H^{i}\left(X,{\mathcal {O}}_{X}(K_{X}+L)\otimes {\mathcal {J}}(D)\right)=0\;\;{\text{for}}\;\;i>0.}

Nadel vanishing theorem in the analytic setting: Let ( X , ω ) {\displaystyle (X,\omega )} be a Kähler manifold (X be a reduced complex space (complex analytic variety) with a Kähler metric) such that weakly pseudoconvex, and let F be a holomorphic line bundle over X equipped with a singular hermitian metric of weight φ {\displaystyle \varphi } . Assume that − 1 ⋅ θ ( F ) > ε ⋅ ω {\displaystyle {\sqrt {-1}}\cdot \theta (F)>\varepsilon \cdot \omega } for some continuous positive function ε {\displaystyle \varepsilon } on X. Then

H i ( X , O X ( K X + F ) ⊗ J ( φ ) ) = 0 for i > 0. {\displaystyle H^{i}\left(X,{\mathcal {O}}_{X}(K_{X}+F)\otimes {\mathcal {J}}(\varphi )\right)=0\;\;{\text{for}}\;\;i>0.}

Let arbitrary plurisubharmonic function ϕ {\displaystyle \phi } on Ω ⊂ X {\displaystyle \Omega \subset X} , then a multiplier ideal sheaf J ( ϕ ) {\displaystyle {\mathcal {J}}(\phi )} is a coherent on Ω {\displaystyle \Omega } , and therefore its zero variety is an analytic set.

References

Citations

Bibliography Nadel, Alan Michael (1989). "Multiplier ideal sheaves and existence of Kähler-Einstein metrics of positive scalar curvature". Proceedings of the National Academy of Sciences of the United States of America. 86 (19): 7299–7300. Bibcode:1989PNAS...86.7299N. doi:10.1073/pnas.86.19.7299. JSTOR 34630. MR 1015491. PMC 298048. PMID 16594070. Nadel, Alan Michael (1990). "Multiplier Ideal Sheaves and Kahler-Einstein Metrics of Positive Scalar Curvature". Annals of Mathematics. 132 (3): 549–596. doi:10.2307/1971429. JSTOR 1971429. Lazarsfeld, Robert (2004). "Multiplier Ideal Sheaves". Positivity in Algebraic Geometry II. pp. 139–231. doi:10.1007/978-3-642-18810-7_5. ISBN 978-3-540-22531-7. Fujino, Osamu (2011). "Fundamental Theorems for the Log Minimal Model Program". Publications of the Research Institute for Mathematical Sciences. 47 (3): 727–789. arXiv:0909.4445. doi:10.2977/PRIMS/50. S2CID 50561502. Demailly, Jean-Pierre (1998–1999). "Méthodes L2 et résultats effectifs en géométrie algébrique". Séminaire Bourbaki. 41: 59–90.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Nadel vanishing theorem

Start with the simplest possible case. Write down what Nadel vanishing theorem claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nadel vanishing theorem before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nadel vanishing theorem ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nadel vanishing theorem

In research
Nadel vanishing theorem appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Nadel vanishing theorem in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Nadel vanishing theorem is common in secondary-school and first-year university syllabi. It links to neighbouring topics Theorems in algebraic geometry, Theorems in complex geometry, so understanding it makes those chapters shorter.
In everyday life
Look for Nadel vanishing theorem outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Nadel vanishing theorem in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Nadel vanishing theorem means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Nadel vanishing theorem out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Nadel vanishing theorem in simple terms?

In mathematics, the Nadel vanishing theorem is a global vanishing theorem for multiplier ideals, introduced by A. M.

Why does Nadel vanishing theorem matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nadel vanishing theorem?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nadel vanishing theorem.

Tags

  • Theorems in algebraic geometry
  • Theorems in complex geometry

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