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Topic: fixed point and retraction theorems
Replies: 9   Last Post: Dec 6, 2013 8:27 AM

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Posts: 5
Registered: 7/28/13
fixed point and retraction theorems
Posted: Nov 15, 2013 11:44 PM
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I was trying to figure out how to solve the following problem concerning a retraction theorem:

Let j:C->D be an inclusion of the circle into the disk. Suppose that we have two continuous maps f:D->D and g:D->D and that g satisfies goj=j. Use the retraction theorem for the disk to show that there must be a point x in the disk at which f(x)=g(x).

Supposedly, this can be proven by constructing a retraction for j by assuming there is no `fixed point' (or something like this), but I am not sure how to do this. Any general suggestion would be greatly appreciated even if they are suggestions of another way of constructing a proof to answer the question.


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