Compact embedding and strong convergence

In summary, compact embedding is a functional analysis concept that describes the relationship between two topological spaces in a compact manner. It differs from strong convergence, which refers to the convergence of a sequence of elements to a limit point. However, compact embedding can be used to prove strong convergence in certain cases. Compact embedding has various applications in mathematics, such as in proving the existence and uniqueness of solutions to problems and establishing important properties of these solutions. Some examples of compact embedding include the Sobolev embedding theorem and the Arzelà–Ascoli theorem. Studying compact embedding and strong convergence allows for a deeper understanding of topological spaces and their properties, with practical applications in fields such as partial differential equations and dynamical systems.
  • #1
NSAC
13
0
Let X be compactly embedded in Y. Assume also that
there is a sequence f_n in X such that
f_n converges to f weakly in X and strongly in Y to some function f in X.
Can we say that f_n converges to f strongly in X?
 
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  • #2
Yes, it's due to the compactness of the embedding.
 
  • #3
Eynstone said:
Yes, it's due to the compactness of the embedding.

Which assumption together with compactness imply this? Weak convergence in X or strong convergence in Y or both? Could you elaborate more?
 

FAQ: Compact embedding and strong convergence

What is compact embedding?

Compact embedding is a concept in functional analysis that describes the relationship between two topological spaces, where one space is embedded into the other in a compact manner. In other words, a compact embedding is a way of mapping a larger space onto a smaller one while preserving certain properties.

What is the difference between compact embedding and strong convergence?

Compact embedding and strong convergence are two distinct concepts in functional analysis. Compact embedding refers to the relationship between two topological spaces, while strong convergence refers to the convergence of a sequence of elements in a space to a specific limit point. However, compact embedding can be used to prove strong convergence in certain cases.

How is compact embedding used in mathematics?

Compact embedding has various applications in mathematics, particularly in functional analysis and differential equations. It is used to prove the existence and uniqueness of solutions to certain problems, as well as to establish important properties of these solutions, such as regularity and convergence.

What are some examples of compact embedding?

One example of compact embedding is the Sobolev embedding theorem, which states that certain functions in a Sobolev space can be continuously embedded into a Lebesgue space. Another example is the Arzelà–Ascoli theorem, which describes the compactness of equicontinuous and uniformly bounded sequences of functions.

What are the benefits of studying compact embedding and strong convergence?

Studying compact embedding and strong convergence allows for a deeper understanding of the relationship between different topological spaces and their properties. It also has practical applications in various fields of mathematics, such as in the analysis of partial differential equations and in the study of dynamical systems.

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