Integration Inequality: f(x) vs g(x)

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Discussion Overview

The discussion revolves around the relationship between two functions, f(x) and g(x), in the context of integration inequalities. Participants explore conditions under which the inequality of the functions implies an inequality of their integrals, focusing on the necessity of certain assumptions about the set E over which the integration is performed.

Discussion Character

  • Mathematical reasoning

Main Points Raised

  • One participant states that if f(x) ≤ g(x) for all x in E, then it follows that ∫_E f ≤ ∫_E g.
  • Another participant questions whether the condition f(x) < g(x) also leads to ∫_E f < ∫_E g, suggesting that additional conditions may be necessary.
  • A participant highlights the importance of specifying that E is a set with non-zero measure, indicating that ∫_E 1 > 0 is a relevant consideration.
  • Another participant adds that the integral should not be infinite for the proposed inequalities to hold true.

Areas of Agreement / Disagreement

Participants generally agree that additional conditions are necessary for the inequalities to hold, particularly regarding the measure of the set E and the finiteness of the integrals. However, the exact implications of these conditions remain under discussion.

Contextual Notes

The discussion does not resolve the implications of the conditions on the inequalities, leaving open questions about the specific requirements for the integrals to maintain the proposed relationships.

JG89
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I know that if [tex]\forall x \in E \subset \mathbb{R}^n[/tex] we have [tex]f(x) \le g(x)[/tex] then it is true that [tex]\int_E f \le \int_E g[/tex].

However, is it also true that if [tex]\forall x \in E[/tex] we have [tex]f(x) < g(x)[/tex] then [tex]\int_E f < \int_E g[/tex]?
 
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Did you mean to also specifiy that [itex]E[/itex] is a set with non-zero measure? i.e.
[tex]\int_E 1 > 0[/tex] ?
 
Yeah. I can see how without giving that extra stipulation what I am asking isn't true.
 
And you probably also want that the integral isn't infinity... In those cases, I think it's true what you're saying...
 

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