0708-1300/Homework Assignment 3: Difference between revisions

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==Just for Fun==
==Just for Fun==
* Trace the proof of the Whitney embedding theorem to find an embedding of the two dimensional real projective plane, <math>{\mathbb R}{\mathbb P}^2=S^2/(p=-p)</math>, inside <math>{\mathbb R}^5</math>. Do not do anything explicitly; just convince yourself that indeed you can find a small atlas (how small?), use it to embed <math>{\mathbb R}{\mathbb P}^2</math> in some large <math>{\mathbb R}^N</math> (how large?), and figure out how many times you will need to use Sard's theorem before you're down to the target, <math>{\mathbb R}^5</math>.
* Now see if you can come up with some cleverer way of viewing <math>{\mathbb R}{\mathbb P}^2</math>, that will allow you to explicitly embed it in <math>{\mathbb R}^5</math>.

Revision as of 08:55, 18 October 2007

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In Preparation

The information below is preliminary and cannot be trusted! (v)

Reading

Read sections 8-10 of chapter II of Bredon's book three times:

  • First time as if you were reading a novel - quickly and without too much attention to detail, just to learn what the main keywords and concepts and goals are.
  • Second time like you were studying for an exam on the subject - slowly and not skipping anything, verifying every little detail.
  • And then a third time, again at a quicker pace, to remind yourself of the bigger picture all those little details are there to paint.

Also, read section 12 of chapter I of Bredon's book, but you can be a little less careful here.

Doing

Solve the following problems from Bredon's book, but submit only the solutions of the problems marked with an "S":

problems on page(s)
1, 2, 3, S4, S5, S6 82
1, 2, S3, S4, 5 86

Due Date

This assignment is due in class on Thursday November 1, 2007.

Just for Fun

  • Trace the proof of the Whitney embedding theorem to find an embedding of the two dimensional real projective plane, [math]\displaystyle{ {\mathbb R}{\mathbb P}^2=S^2/(p=-p) }[/math], inside [math]\displaystyle{ {\mathbb R}^5 }[/math]. Do not do anything explicitly; just convince yourself that indeed you can find a small atlas (how small?), use it to embed [math]\displaystyle{ {\mathbb R}{\mathbb P}^2 }[/math] in some large [math]\displaystyle{ {\mathbb R}^N }[/math] (how large?), and figure out how many times you will need to use Sard's theorem before you're down to the target, [math]\displaystyle{ {\mathbb R}^5 }[/math].
  • Now see if you can come up with some cleverer way of viewing [math]\displaystyle{ {\mathbb R}{\mathbb P}^2 }[/math], that will allow you to explicitly embed it in [math]\displaystyle{ {\mathbb R}^5 }[/math].