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analytic curve (Definition)

There are several somewhat different definitions of the word analytic curve depending on context. In the context of a real analytic manifold (for example $ {\mathbb{R}}^n$), the most generic definition is perhaps the following.

Definition 1   Suppose $ X$ is a real analytic manifold. A curve $ \gamma \subset X$ is an analytic curve if it is a real analytic submanifold of dimension 1. Equivalently if near each point $ p \in \gamma,$ there exists a real analytic mapping $ f \colon (-1,1) \to X,$ such that $ f$ has nonvanishing differential and maps onto a neighbourhood of $ p$ in $ \gamma .$

It is sometimes common to equate the mapping $ f$ and the curve $ \gamma$. If the curve is as above but instead in the complex plane, we can instead make the following equivalent definition.

Definition 2   A curve $ \gamma \subset \mathbb{C}$ is said to be an analytic curve (or analytic arc) if every point of $ \gamma$ has an open neighbourhood $ \Delta$ for which there is an onto conformal map $ f \colon {\mathbb{D}} \to \Delta$ (where $ {\mathbb{D}} \subset \mathbb{C}$ is the unit disc) such that $ {\mathbb{D}} \cap {\mathbb{R}}$ is mapped onto $ \Delta \cap \gamma$ by $ f.$

Other words for this concept are smooth analytic curve, in which case the word analytic curve would be reserved for curves with singularities. That is, for real analytic subvarieties of $ X$. Some authors will emphasize the fact that this is a real curve and say real analytic curve.

In the context of subvarieties the following definition may be used.

Definition 3   An analytic curve is a complex analytic subvariety of dimension 1 of a complex manifold.

Note that locally all complex analytic subvarieties of dimension 1 in $ {\mathbb{C}}^2$ can be parametrized by a the Puiseux parametrization theorem. Perhaps that is why there is the confusion in using the term.

Bibliography

1
Theodore B. Gamelin. Complex Analysis. Springer-Verlag, New York, New York, 2001.
2
Hassler Whitney. Complex Analytic Varieties. Addison-Wesley, Philippines, 1972.



"analytic curve" is owned by jirka.
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See Also: free analytic boundary arc

Other names:  analytic arc, smooth analytic curve, real analytic curve
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Cross-references: term, Puiseux parametrization, complex manifold, complex analytic subvariety, subvarieties, real, real analytic subvarieties, unit disc, conformal, open, equivalent, complex plane, equate, neighbourhood, onto, maps, mapping, point, near, dimension, real analytic submanifold, curve, generic, manifold, real analytic, definitions
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This is version 4 of analytic curve, born on 2004-04-13, modified 2007-12-05.
Object id is 5759, canonical name is AnalyticCurve.
Accessed 3048 times total.

Classification:
AMS MSC54-00 (General topology :: General reference works )
 30-00 (Functions of a complex variable :: General reference works )

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