Definition 2.21. Let X be a space. Let A be a subset of X. We say that a point x € X is a limit point of A iff for every open set U in X containing x, (U \ {x}) nA # 0. The set of limit points of A is denoted A'. Exercise 2.22. Let E CN be the set of even natural numbers. Give N the Ta topology (see Exercise 2.12). What is E'? What is E?

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
icon
Concept explainers
Topic Video
Question

Solve 2.23 

I posted this question an hour ago and somebody posted the answer from chegg ( copied and pasted it) don't do that please I will report it otherwise.

Definition 2.21. Let X be a space. Let A be a subset of X. We say that a point x E X
is a limit point of A iff for every open set U in X containing x, (U \ {x})n A ± Ø. The set
of limit points of A is denoted A'.
Exercise 2.22. Let E C N be the set of even natural numbers. Give N the Ta topology (see
Exercise 2.12). What is E'? What is E?
Problem 2.23. Let E C N be the set of even natural numbers. Give N the cofinite topology.
What is E'? What is E?
Transcribed Image Text:Definition 2.21. Let X be a space. Let A be a subset of X. We say that a point x E X is a limit point of A iff for every open set U in X containing x, (U \ {x})n A ± Ø. The set of limit points of A is denoted A'. Exercise 2.22. Let E C N be the set of even natural numbers. Give N the Ta topology (see Exercise 2.12). What is E'? What is E? Problem 2.23. Let E C N be the set of even natural numbers. Give N the cofinite topology. What is E'? What is E?
Expert Solution
Step 1

Note: According to Bartleby guidelines; for more than one question asked, only the first one is to be answered.

Given X= and A=E where E is the set of all even natural numbers.

Here Ta=Y| Y is a subset of 

Let a.

Claim: a is not a limit point of E.

Consider Y=a.

Then YTa and hence is a open set of  which contains a.

But then, Y\aE=

Hence we have found a open set Y of containing a such that Y\aE=.

Therefore, it follows that a is not a limit point of E.

Since a is arbitrary it follows that no natural number is a limit point of E.

Therefore, E'=

 

trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps

Blurred answer
Knowledge Booster
Application of Algebra
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, advanced-math and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,