Theorem 4.7. (1) A T2-space (Hausdorff) is a T1-space. (2) A T3-space (regular and T¡) is a Hausdorff space, that is, a T2-space. (3) A T4-space (normal and T¡) is regular and T,, that is, a T3-space.

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
Topic Video
Question
100%

Could you explain to me how to show 4.7 in detail?

**Theorem 4.7.** 

1. A \( T_2 \)-space (Hausdorff) is a \( T_1 \)-space.

2. A \( T_3 \)-space (regular and \( T_1 \)) is a Hausdorff space, that is, a \( T_2 \)-space.

3. A \( T_4 \)-space (normal and \( T_1 \)) is regular and \( T_1 \), that is, a \( T_3 \)-space.

**Definition.** Let \( (X, \mathcal{T}) \) be a topological space.

1. \( X \) is a \( T_1 \)-space if and only if for every pair \( x, y \) of distinct points there are open sets \( U, V \) such that \( U \) contains \( x \) but not \( y \), and \( V \) contains \( y \) but not \( x \).

2. \( X \) is Hausdorff, or a \( T_2 \)-space, if and only if for every pair \( x, y \) of distinct points there are disjoint open sets \( U, V \) such that \( x \in U \) and \( y \in V \).

3. \( X \) is regular if and only if for every point \( x \in X \) and closed set \( A \subset X \) not containing \( x \), there are disjoint open sets \( U, V \) such that \( x \in U \) and \( A \subset V \). A \( T_3 \)-space is any space that is both \( T_1 \) and regular.

4. \( X \) is normal if and only if for every pair of disjoint closed sets \( A, B \) in \( X \), there are disjoint open sets \( U, V \) such that \( A \subset U \) and \( B \subset V \). A \( T_4 \)-space is any space that is both \( T_1 \) and normal.
Transcribed Image Text:**Theorem 4.7.** 1. A \( T_2 \)-space (Hausdorff) is a \( T_1 \)-space. 2. A \( T_3 \)-space (regular and \( T_1 \)) is a Hausdorff space, that is, a \( T_2 \)-space. 3. A \( T_4 \)-space (normal and \( T_1 \)) is regular and \( T_1 \), that is, a \( T_3 \)-space. **Definition.** Let \( (X, \mathcal{T}) \) be a topological space. 1. \( X \) is a \( T_1 \)-space if and only if for every pair \( x, y \) of distinct points there are open sets \( U, V \) such that \( U \) contains \( x \) but not \( y \), and \( V \) contains \( y \) but not \( x \). 2. \( X \) is Hausdorff, or a \( T_2 \)-space, if and only if for every pair \( x, y \) of distinct points there are disjoint open sets \( U, V \) such that \( x \in U \) and \( y \in V \). 3. \( X \) is regular if and only if for every point \( x \in X \) and closed set \( A \subset X \) not containing \( x \), there are disjoint open sets \( U, V \) such that \( x \in U \) and \( A \subset V \). A \( T_3 \)-space is any space that is both \( T_1 \) and regular. 4. \( X \) is normal if and only if for every pair of disjoint closed sets \( A, B \) in \( X \), there are disjoint open sets \( U, V \) such that \( A \subset U \) and \( B \subset V \). A \( T_4 \)-space is any space that is both \( T_1 \) and normal.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 6 steps

Blurred answer
Knowledge Booster
Algebraic Operations
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,