Regarding Schwartz inequality and integration bounds

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Discussion Overview

The discussion revolves around the application of the Cauchy-Schwarz inequality in the context of integration bounds, specifically addressing the presence of a variable "s" as a lower bound in an inequality involving integrals of functions defined by products of other functions.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant questions the necessity of the "s" variable as a lower bound in the inequality derived from the Schwartz inequality, suggesting an alternative form without it.
  • Another participant suggests applying the Cauchy-Schwarz inequality to specific functions defined in the context of the problem, indicating a method to analyze the inequality.
  • A participant expresses confusion regarding the implications of a small "s" value, noting that while it may lead to a small upper bound, it remains mathematically valid despite potential physical implications.

Areas of Agreement / Disagreement

The discussion features multiple competing views regarding the role of the "s" variable in the inequality, and it remains unresolved whether its inclusion is necessary or beneficial.

Contextual Notes

Participants have not fully explored the implications of varying "s" or the specific conditions under which the inequalities hold, leaving some assumptions unaddressed.

p4wp4w
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Based on Schwartz inequality, I am trying to figure out why there
should/can be the "s" variable which is the lower bound of the
integration in the RHS of the following inequality:
## \left \|\int_{-s}^{0} A(t+r)Z(t+r) dr \right \|^{2} \leq s\int_{-s}^{0}\left \| A(t+r)Z(t+r) \right \|^{2} dr, ##
instead of:
## \left \|\int_{-s}^{0} A(t+r)Z(t+r) dr \right \|^{2} \leq \int_{-s}^{0}\left \| A(t+r)Z(t+r) \right \|^{2} dr. ##
 
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p4wp4w said:
Based on Schwartz inequality, I am trying to figure out why there
should/can be the "s" variable which is the lower bound of the
integration in the RHS of the following inequality:
## \left \|\int_{-s}^{0} A(t+r)Z(t+r) dr \right \|^{2} \leq s\int_{-s}^{0}\left \| A(t+r)Z(t+r) \right \|^{2} dr, ##
instead of:
## \left \|\int_{-s}^{0} A(t+r)Z(t+r) dr \right \|^{2} \leq \int_{-s}^{0}\left \| A(t+r)Z(t+r) \right \|^{2} dr. ##
Apply the Cauchy-Schwarz inequality to the functions##f,\ g## defined by ##f(r)=A(t+r)Z(t+r)## and ##g(r)=1##.
 
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Samy_A said:
Apply the Cauchy-Schwarz inequality to the functions##f,\ g## defined by ##f(r)=A(t+r)Z(t+r)## and ##g(r)=1##.
Sure. My confusion was because of the example in my mind that s can be a very small value which then the upper bound will be also very small and as a result, physically conservatism but again mathematically correct. Thank you very much.
 

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