Negating a Universal Statement in Real Analysis

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The discussion focuses on the correct negation of a universal statement in real analysis regarding sequences. The original statement asserts that for every positive epsilon, there exists an N such that for all n, m greater than or equal to N, the difference between the functions f_n and f_m is less than epsilon. The correct negation involves stating that there exists a positive epsilon for which no N can be found such that the property holds, leading to the formulation: there exists an epsilon greater than zero, for all N, there exist n and m greater than or equal to N such that the difference is at least epsilon. The participants clarify the logical structure needed to accurately express this negation.
bguidinger
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I am stuck in trying to take the negation of this statement:

(\forall \varepsilon>0)(\exists N \in N)(\forall n,m\geq N)(\forall x \in R [|f_n(x)-f_m(x)|< \varepsilon]

One of my thoughts was that in order to move the negation inside the brackets, all I need to do is say (\exists \varepsilon \leq 0)...and everything else remains unchanged.

However, my other thought was to somehow move the statement \varepsilon > 0 to the end of the original statement and make it: (\varepsilon > 0 \Rightarrow |f_n(x)-f_m(x)|< \varepsilon)

If you can help me in anyway, it would be greatly appreciated.

Thanks!
 
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It seems like you need something like there exists an eps >0 for which there is no N for the property (a Cauchy sequence in the sup norm topology).
 
I figured it out...here is the solution for anyone who is curious.

(\exists \varepsilon>0)(\forall N \in N)(\exists n,m\geq N)(\exists x \in R [|f_n(x)-f_m(x)| \geq \varepsilon]

Thanks for the help!
 

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