CSIR-NET: Analysis/Topology Quiz 1


Let A be a closed subset of . Then A is

The closure of interior of A
Hint: Is {1, 3, 5} closed? What can you say about the closure of interior of this set?

A countable set
Hint: Is closed? Is it countable? You can try guess the answer again!

A compact set
Hint: Is closed? Is it compact? You can try guess the answer again!

Not open
is a connected space. And by the definition of connected space, only open and closed sets are . Watch more solutions in this video.

CSIR-NET December 2015, Part B Question.

How should I analyze this question when I am preparing for CSIR-NET?

  1. Mark all mathematical terms here. Read their definitions.
  2. Try construct examples for each terms, try apply it in options.
  3. This question is interesting because it talks about a lot of mathematical terms, but the keyword is nowhere mentioned in question – connected spaces. Read and analyse that definition, too.
  4. Make a note of all your observations, examples that you found, in your NET preparation diary. For example, you should have asked questions like:
    1. Why did they say closure of interior of A, and not interior of closure of A? Will there be any difference?
    2. How will countable closed sets look like?
    3. Can there be countable open sets?
    4. Are there any other sets which are connected, like \mathbb R?
    5. Can I characterize compact sets which are not closed in \mathbb R?

Once you are done, try watching the following video. Is there any other ways to solve the same question?

Consider buying one of the following suggested books, if you do not have it yet.

Recommended Books for Real Analysis

Click on the image to buy.

https://m.media-amazon.com/images/I/51KgfU+RvgL._SL160_.jpg
Introduction to Real Analysis by Bartle and Sherbert (4e)
https://m.media-amazon.com/images/I/31rJbDUVh7L._SL160_.jpg
Principles of Mathematical Analysis by Rudin
https://m.media-amazon.com/images/I/21xmoHk2GNL._SL160_.jpg
Real Analysis by Kumaresan
https://m.media-amazon.com/images/I/41icXR1neqL._SL160_.jpg
Introduction to Topology and Modern Analysis by Simmons
https://m.media-amazon.com/images/I/418FX7j0koL._SL160_.jpg
Topology of Metric Spaces

One Comment Add yours

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.