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=Problems that we have not yet done=
 
=Problems that we have not yet done=
  
==Practice Exam 4==
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==Practice Exam 4==  
 
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2. Let <math>(X,\mathcal{M}, \mu)</math> be a measure space with <math>\mu(X) =1</math> and let <math>F_1, \ldots, F_{17}</math> be seventeen measurable subsets of <math>X</math> with <math>\mu(F_j)=\frac{1}{4}</math> for every <math>j</math>.
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a. Prove that (some) five of these subsets must have an intersection of positive measure.
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b. Is the conclusion above true if we take sixteen sets instead of seventeen?
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5. Let <math>(X,\mathcal{M}, \mu)</math> be a measure space with <math>0<\mu(X) < \infty</math>. Assume that <math>f_n \to f</math> <math>\mu</math>-a.e. and <math>\|f_n\|_p \leq M < \infty</math> for some <math>1<p<\infty</math>. If <math>1\leq r <p</math>, show that <math>f_n \to f</math>/math> in <math>L^r</math>.
 
5. Let <math>(X,\mathcal{M}, \mu)</math> be a measure space with <math>0<\mu(X) < \infty</math>. Assume that <math>f_n \to f</math> <math>\mu</math>-a.e. and <math>\|f_n\|_p \leq M < \infty</math> for some <math>1<p<\infty</math>. If <math>1\leq r <p</math>, show that <math>f_n \to f</math>/math> in <math>L^r</math>.
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4. For <math>n=1,2,\ldots</math>, let <math>f_n:I\to \mathbb{R}, I =[a,b]</math> be a subsequence of functions satisfying the following: If <math>\{x_n\}</math> is a Cauchy sequence in <math>I</math>, then <math>\{f_n(x_n)\}</math> is also a Cauchy sequence. Show that <math>\{f_n\}</math> converges uniformly on <math>I</math>.
 
4. For <math>n=1,2,\ldots</math>, let <math>f_n:I\to \mathbb{R}, I =[a,b]</math> be a subsequence of functions satisfying the following: If <math>\{x_n\}</math> is a Cauchy sequence in <math>I</math>, then <math>\{f_n(x_n)\}</math> is also a Cauchy sequence. Show that <math>\{f_n\}</math> converges uniformly on <math>I</math>.
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==later==
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problem 3 on practice exams 7, 8, 9, and 10
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problem 5 on practice exam 11
  
 
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[[ 2010 Summer MA 598 Hackney|Back to 2010 Summer MA 598 Hackney]]

Revision as of 04:54, 26 July 2010


Problems that we have not yet done

Practice Exam 4

5. Let $ (X,\mathcal{M}, \mu) $ be a measure space with $ 0<\mu(X) < \infty $. Assume that $ f_n \to f $ $ \mu $-a.e. and $ \|f_n\|_p \leq M < \infty $ for some $ 1<p<\infty $. If $ 1\leq r <p $, show that $ f_n \to f $/math> in $ L^r $.


Practice Exam 6

4. For $ n=1,2,\ldots $, let $ f_n:I\to \mathbb{R}, I =[a,b] $ be a subsequence of functions satisfying the following: If $ \{x_n\} $ is a Cauchy sequence in $ I $, then $ \{f_n(x_n)\} $ is also a Cauchy sequence. Show that $ \{f_n\} $ converges uniformly on $ I $.

later

problem 3 on practice exams 7, 8, 9, and 10

problem 5 on practice exam 11

Back to 2010 Summer MA 598 Hackney

Alumni Liaison

Ph.D. 2007, working on developing cool imaging technologies for digital cameras, camera phones, and video surveillance cameras.

Buyue Zhang