Question about elementary topology

In summary, the conversation discusses whether the product of closed sets is closed in the product topology. The participants mention that it is true for finite products, but there is some uncertainty for infinite products. They also mention using a different basis for infinite products and confirm that the statement is true for infinite products with a simple proof.
  • #1
facenian
436
25
Hello, I've got a simple question
is the product of closed sets closed in the product topology?
I think the answer is yes but need to sure
 
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  • #2
Use the fact for product topologies that the closure of the product is the product of the closures.
 
  • #3
It is true for finite product, but I am not so sure it is true for infinite products.

For a product of finitely many spaces, the base is given by the product of
all open sets , i.e., given spaces X_1,..,X_n , and U_i open in X_i , then
U_1 xU_2 x...xU_n is open in the product and a basis element.

For infinite products, you need a different basis.
 
  • #4
Thank you guys, I think we can use what VeeEight says which true for the infinite casa as well
 
  • #5
Yes, it is true for infinite products and is a simple proof. Hope that helps.
 

FAQ: Question about elementary topology

1. What is elementary topology?

Elementary topology is a branch of mathematics that studies the properties and relationships of geometric objects, such as points, lines, curves, and surfaces. It deals with concepts such as continuity, connectedness, and convergence, and provides a framework for understanding the structure of spaces and their transformations.

2. What are some basic concepts in elementary topology?

Some basic concepts in elementary topology include open and closed sets, neighborhoods, compactness, continuity, and homeomorphisms. These concepts help define the topological structure of a space and allow for the exploration of its properties and transformations.

3. How is elementary topology different from other branches of topology?

Elementary topology is more focused on the basic principles and foundations of topology, whereas other branches of topology may be more specialized and deal with advanced or specific topics. Elementary topology provides a strong foundation for understanding other branches of topology.

4. What are some real-world applications of elementary topology?

Elementary topology has many practical applications in fields such as physics, engineering, computer science, and biology. It can be used to model and analyze complex systems, study the behavior of networks and data structures, and understand the shape and structure of biological molecules.

5. How can I learn more about elementary topology?

There are many resources available for learning about elementary topology, including textbooks, online courses, and videos. It is also helpful to have a solid foundation in calculus and linear algebra before delving into topology. Additionally, practicing problem-solving and thinking abstractly can aid in understanding the concepts of elementary topology.

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