Calculating a metric from a norm and inner product.

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SUMMARY

The discussion focuses on calculating the supremum of the expression |1 - x| over specific intervals [a, b]. Participants confirm that the supremum varies based on the interval, with examples provided: for [a, b] = [-500, 1], the supremum is 501, while for [a, b] = [-1, 500], it is 499. Additionally, there is a query regarding the relationship of norms to the unit circle, with suggestions to use sample points for visualization. The final problem is confirmed as complete by the original poster.

PREREQUISITES
  • Understanding of supremum and norm concepts in mathematical analysis.
  • Familiarity with the function space C([0,1]) and its properties.
  • Basic knowledge of trigonometry, particularly the unit circle.
  • Experience with LaTeX for mathematical notation.
NEXT STEPS
  • Study the properties of supremum in different mathematical contexts.
  • Explore the concept of norms in functional analysis.
  • Learn about the implications of the unit circle in higher dimensions.
  • Practice using LaTeX for mathematical expressions and proofs.
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Mathematicians, students in advanced calculus or analysis courses, and anyone interested in understanding norms and supremum calculations in functional spaces.

jdinatale
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I typed the problem in latex and will add comments below each image.

norm1.png


The supremum of |1 - x| seems dependent on the interval [a, b]. For instance, if [a, b] = [-500, 1], then 501 is the supremum of |1 - x|. But if [a, b] = [-1, 500], then 499 is the supremum of [1 - x]. So what should I say?

norm2.png


For this one, I'm not sure if I did it correctly. So could someone just verify that my solution is correct?

norm3.png


I'm really not sure how to do this one. I'm trying to relate it to the unit circle from trigonometry, but that had an x and y coordinate...For this one, would I just choose sample points (1, 0), (0, 1), (-1, 0), and (0, -1) and sketch the norm at each of these? But the norm only takes 1 value, not two...
 
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Q1. C([0,1])="the function space of continuous functions defined on the interval [0,1]" so [0,1] is fixed, you cannot shift it around.

Q2. last step is wrong.

Q3. a Ball={set of all x in ? such that Norm(x-0)<=radius"} it is implied in the question what ? is.
 
xaos said:
Q1. C([0,1])="the function space of continuous functions defined on the interval [0,1]" so [0,1] is fixed, you cannot shift it around.

Q2. last step is wrong.

Q3. a Ball={set of all x in ? such that Norm(x-0)<=radius"} it is implied in the question what ? is.

thank you, i have the problem complete now!
 

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