Approaching Openness in R^2: Investigating Open Balls

  • Thread starter Thread starter jdinatale
  • Start date Start date
  • Tags Tags
    Balls
Click For Summary
SUMMARY

The discussion centers on the concept of openness in R^2, specifically regarding the characterization of open sets using open balls. Participants assert that if a set is open, its complement is closed, and they explore the implications of approaching the set from various directions. The conversation emphasizes the necessity of precise definitions and the application of open balls to articulate the properties of open sets in two-dimensional space.

PREREQUISITES
  • Understanding of open sets in topology
  • Familiarity with the concept of open balls in metric spaces
  • Basic knowledge of R^2 (two-dimensional Euclidean space)
  • Comprehension of closed sets and their complements
NEXT STEPS
  • Study the definition and properties of open sets in topology
  • Learn how to construct open balls in R^2
  • Investigate the relationship between open and closed sets
  • Explore examples of open sets and their complements in R^2
USEFUL FOR

Mathematicians, students of topology, and anyone interested in the foundational concepts of open and closed sets in two-dimensional spaces.

jdinatale
Messages
153
Reaction score
0
I typed the question and my attempt at a solution below...

euclidmetric.png


It seems obviously open to me, but I'm not sure how to state it using open balls considering that it's in R^2.
 
Physics news on Phys.org


jdinatale said:
I typed the question and my attempt at a solution below...

euclidmetric.png


It seems obviously open to me, but I'm not sure how to state it using open balls considering that it's in R^2.

If it's open, its complement is closed. What happens if you sneak up to it from above? Or below?
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
3
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
Replies
1
Views
2K