How to construct a homeomorphism on closed unit disc onto itself which fixes boundary point wise?












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How can we construct a homeomorphism on closed disc onto itself which fixes boundary pointwise? What is the starting point.










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  • 2




    $begingroup$
    You could use the identity... it fixes the boundary (and all other points).
    $endgroup$
    – Clayton
    Jan 8 at 22:54










  • $begingroup$
    Well that is trivial! I am looking for non-trivial ones.
    $endgroup$
    – ersh
    Jan 8 at 22:56










  • $begingroup$
    How can I write the formula for this transformation?
    $endgroup$
    – ersh
    Jan 8 at 23:02






  • 3




    $begingroup$
    $f(r,theta)=(r,theta+2pi r)$
    $endgroup$
    – Lee Mosher
    Jan 8 at 23:15






  • 2




    $begingroup$
    @kesa OP is looking for maps that fix every point on the boundary. The only holomorphic map that does this is the identity.
    $endgroup$
    – Kavi Rama Murthy
    Jan 8 at 23:23
















0












$begingroup$


How can we construct a homeomorphism on closed disc onto itself which fixes boundary pointwise? What is the starting point.










share|cite|improve this question











$endgroup$








  • 2




    $begingroup$
    You could use the identity... it fixes the boundary (and all other points).
    $endgroup$
    – Clayton
    Jan 8 at 22:54










  • $begingroup$
    Well that is trivial! I am looking for non-trivial ones.
    $endgroup$
    – ersh
    Jan 8 at 22:56










  • $begingroup$
    How can I write the formula for this transformation?
    $endgroup$
    – ersh
    Jan 8 at 23:02






  • 3




    $begingroup$
    $f(r,theta)=(r,theta+2pi r)$
    $endgroup$
    – Lee Mosher
    Jan 8 at 23:15






  • 2




    $begingroup$
    @kesa OP is looking for maps that fix every point on the boundary. The only holomorphic map that does this is the identity.
    $endgroup$
    – Kavi Rama Murthy
    Jan 8 at 23:23














0












0








0





$begingroup$


How can we construct a homeomorphism on closed disc onto itself which fixes boundary pointwise? What is the starting point.










share|cite|improve this question











$endgroup$




How can we construct a homeomorphism on closed disc onto itself which fixes boundary pointwise? What is the starting point.







general-topology group-theory analysis differential-geometry






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 8 at 22:57







ersh

















asked Jan 8 at 22:52









ershersh

438113




438113








  • 2




    $begingroup$
    You could use the identity... it fixes the boundary (and all other points).
    $endgroup$
    – Clayton
    Jan 8 at 22:54










  • $begingroup$
    Well that is trivial! I am looking for non-trivial ones.
    $endgroup$
    – ersh
    Jan 8 at 22:56










  • $begingroup$
    How can I write the formula for this transformation?
    $endgroup$
    – ersh
    Jan 8 at 23:02






  • 3




    $begingroup$
    $f(r,theta)=(r,theta+2pi r)$
    $endgroup$
    – Lee Mosher
    Jan 8 at 23:15






  • 2




    $begingroup$
    @kesa OP is looking for maps that fix every point on the boundary. The only holomorphic map that does this is the identity.
    $endgroup$
    – Kavi Rama Murthy
    Jan 8 at 23:23














  • 2




    $begingroup$
    You could use the identity... it fixes the boundary (and all other points).
    $endgroup$
    – Clayton
    Jan 8 at 22:54










  • $begingroup$
    Well that is trivial! I am looking for non-trivial ones.
    $endgroup$
    – ersh
    Jan 8 at 22:56










  • $begingroup$
    How can I write the formula for this transformation?
    $endgroup$
    – ersh
    Jan 8 at 23:02






  • 3




    $begingroup$
    $f(r,theta)=(r,theta+2pi r)$
    $endgroup$
    – Lee Mosher
    Jan 8 at 23:15






  • 2




    $begingroup$
    @kesa OP is looking for maps that fix every point on the boundary. The only holomorphic map that does this is the identity.
    $endgroup$
    – Kavi Rama Murthy
    Jan 8 at 23:23








2




2




$begingroup$
You could use the identity... it fixes the boundary (and all other points).
$endgroup$
– Clayton
Jan 8 at 22:54




$begingroup$
You could use the identity... it fixes the boundary (and all other points).
$endgroup$
– Clayton
Jan 8 at 22:54












$begingroup$
Well that is trivial! I am looking for non-trivial ones.
$endgroup$
– ersh
Jan 8 at 22:56




$begingroup$
Well that is trivial! I am looking for non-trivial ones.
$endgroup$
– ersh
Jan 8 at 22:56












$begingroup$
How can I write the formula for this transformation?
$endgroup$
– ersh
Jan 8 at 23:02




$begingroup$
How can I write the formula for this transformation?
$endgroup$
– ersh
Jan 8 at 23:02




3




3




$begingroup$
$f(r,theta)=(r,theta+2pi r)$
$endgroup$
– Lee Mosher
Jan 8 at 23:15




$begingroup$
$f(r,theta)=(r,theta+2pi r)$
$endgroup$
– Lee Mosher
Jan 8 at 23:15




2




2




$begingroup$
@kesa OP is looking for maps that fix every point on the boundary. The only holomorphic map that does this is the identity.
$endgroup$
– Kavi Rama Murthy
Jan 8 at 23:23




$begingroup$
@kesa OP is looking for maps that fix every point on the boundary. The only holomorphic map that does this is the identity.
$endgroup$
– Kavi Rama Murthy
Jan 8 at 23:23










1 Answer
1






active

oldest

votes


















5












$begingroup$

u can just do a rotation which tend to zero angle when you go torward the boundary and to some other angle while you are going torward the centre






share|cite|improve this answer









$endgroup$













  • $begingroup$
    How would I write such a map?
    $endgroup$
    – ersh
    Jan 8 at 23:32






  • 3




    $begingroup$
    polar coordinates
    $endgroup$
    – tommycautero
    Jan 8 at 23:36










  • $begingroup$
    Yes!..let me try.
    $endgroup$
    – ersh
    Jan 8 at 23:37












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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









5












$begingroup$

u can just do a rotation which tend to zero angle when you go torward the boundary and to some other angle while you are going torward the centre






share|cite|improve this answer









$endgroup$













  • $begingroup$
    How would I write such a map?
    $endgroup$
    – ersh
    Jan 8 at 23:32






  • 3




    $begingroup$
    polar coordinates
    $endgroup$
    – tommycautero
    Jan 8 at 23:36










  • $begingroup$
    Yes!..let me try.
    $endgroup$
    – ersh
    Jan 8 at 23:37
















5












$begingroup$

u can just do a rotation which tend to zero angle when you go torward the boundary and to some other angle while you are going torward the centre






share|cite|improve this answer









$endgroup$













  • $begingroup$
    How would I write such a map?
    $endgroup$
    – ersh
    Jan 8 at 23:32






  • 3




    $begingroup$
    polar coordinates
    $endgroup$
    – tommycautero
    Jan 8 at 23:36










  • $begingroup$
    Yes!..let me try.
    $endgroup$
    – ersh
    Jan 8 at 23:37














5












5








5





$begingroup$

u can just do a rotation which tend to zero angle when you go torward the boundary and to some other angle while you are going torward the centre






share|cite|improve this answer









$endgroup$



u can just do a rotation which tend to zero angle when you go torward the boundary and to some other angle while you are going torward the centre







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jan 8 at 23:01









tommycauterotommycautero

888




888












  • $begingroup$
    How would I write such a map?
    $endgroup$
    – ersh
    Jan 8 at 23:32






  • 3




    $begingroup$
    polar coordinates
    $endgroup$
    – tommycautero
    Jan 8 at 23:36










  • $begingroup$
    Yes!..let me try.
    $endgroup$
    – ersh
    Jan 8 at 23:37


















  • $begingroup$
    How would I write such a map?
    $endgroup$
    – ersh
    Jan 8 at 23:32






  • 3




    $begingroup$
    polar coordinates
    $endgroup$
    – tommycautero
    Jan 8 at 23:36










  • $begingroup$
    Yes!..let me try.
    $endgroup$
    – ersh
    Jan 8 at 23:37
















$begingroup$
How would I write such a map?
$endgroup$
– ersh
Jan 8 at 23:32




$begingroup$
How would I write such a map?
$endgroup$
– ersh
Jan 8 at 23:32




3




3




$begingroup$
polar coordinates
$endgroup$
– tommycautero
Jan 8 at 23:36




$begingroup$
polar coordinates
$endgroup$
– tommycautero
Jan 8 at 23:36












$begingroup$
Yes!..let me try.
$endgroup$
– ersh
Jan 8 at 23:37




$begingroup$
Yes!..let me try.
$endgroup$
– ersh
Jan 8 at 23:37


















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