Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Topology Exam 1: September 30, 2008 - Prof. Isabel K. Darcy, Exams of Topology

A topology exam from september 30, 2008. It includes questions on limit points, sets in the real numbers, and false statements about topology. Students are required to prove two of three statements and show that a metric generates the standard topology on r2.

Typology: Exams

Pre 2010

Uploaded on 09/17/2009

koofers-user-xwb
koofers-user-xwb 🇺🇸

10 documents

1 / 3

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
22M:132: Topology Exam 1
Sept 30, 2008
[10] 1.) Definition: The point xXis a limit point of Aif
[12] 2.) Suppose R= the set of real numbers has the standard topology. Let Q= the set of
rational numbers. Calculate the following in R:
Qo=Q=Q0=
3.) The following two statements are false. Show that the statements are false by providing counter-
examples. You do not need to explain your counter-examples.
[9] 3a.) If xnA, then there exists a unique point xAsuch that xnx.
[9] 3b.) If f:XYis continuous, then f(A)f(A).
1
pf3

Partial preview of the text

Download Topology Exam 1: September 30, 2008 - Prof. Isabel K. Darcy and more Exams Topology in PDF only on Docsity!

22M:132: Topology Exam 1 Sept 30, 2008

[10] 1.) Definition: The point x ∈ X is a limit point of A if

[12] 2.) Suppose R = the set of real numbers has the standard topology. Let Q = the set of rational numbers. Calculate the following in R:

Q o^ = Q = Q ′^ =

3.) The following two statements are false. Show that the statements are false by providing counter- examples. You do not need to explain your counter-examples.

[9] 3a.) If xn ∈ A, then there exists a unique point x ∈ A such that xn → x.

[9] 3b.) If f : X → Y is continuous, then f (A) ⊂ f (A).

[60] Prove 2 of the following 3. Clearly indicate your choices.

  1. The product of two Hausdorff spaces is Hausdorff.
  2. Let Y be a subspace of X. If A ⊂ Y , then ClY (A) = A ∩ Y.
  3. Show that D((x 1 , y 1 ), (x 2 , y 2 )) = max{|x 1 − y 1 |, |x^2 − 2 y^2 |} is a metric on R^2 where (xi, yi) ∈ R^2. Show that this metric generates the standard topology on R^2.