Bounding p-norm expression using p-norm inequality

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SUMMARY

The discussion centers on bounding the expression ||w||_p^2 + ||u||_p^2 - 2(||u||_p^p)^{\frac{2}{p}-1}Σ_i(u(i)^{p-1}w(i)) as a function of ||w-u||_p^2 for p in the range [2, ∞). The user suspects that this expression is less than or equal to ||w-u||_p^2 but struggles to provide a formal justification. The equality holds for p=2, indicating a potential application of p-norm inequalities to establish the upper bound for other values of p.

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problem statement:

need to show:
||w||_p^2+||u||_p^2-2(||u||_p^p)^{\frac{2}{p}-1}\Sigma_i(u(i)^{p-1}w(i))

can be bounded as a function of

||w-u||_p^2

where p\in[2,\infty)

work done:

the expressions are equal for p=2, and i suspect that

||w||_p^2+||u||_p^2-2(||u||_p^p)^{\frac{2}{p}-1}\Sigma_i(u(i)^{p-1}w(i)) \leq||w-u||_p^2

but i get stuck here. Is there some kind of p-norm inequality I can apply here?Thank you!
 
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Forum rules require you to show your work. From what I see, you just took the problem statement and re-wrote it with "I suspect that" it holds as an upper bound with a scalar multiple of one.

What kind of work can you show to at least justify your suspicion?
 
Last edited:

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