Definition of a Divergent Sequence
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I have that the definition of a convergent sequence is:

($\exists$ L $\in$ $\mathbb{R}$)($\forall$ $\epsilon$ > 0)($\exists$ N $\in$ $\mathbb{N}$)($\forall$ n $\in$ $\mathbb{N}$)[n $\ge$ N $\Rightarrow$ |$x_n-L|$ < $\epsilon$]

Would it follow that the definition of divergence is the negation:

($\forall$ L $\in$ $\mathbb{R}$)($\exists$ $\epsilon$ > 0)($\forall$ N $\in$ $\mathbb{N}$)($\exists$ n $\in$ $\mathbb{N}$)[n $\ge$ N and |$x_n-L|$ $\ge$ $\epsilon$]

or would it simply be the definition of convergence except making it so there does not exist L in the reals so:

(∄ L $\in$ $\mathbb{R}$)($\forall$ $\epsilon$ > 0)($\exists$ N $\in$ $\mathbb{N}$)($\forall$ n $\in$ $\mathbb{N}$)[n $\ge$ N $\Rightarrow$ |$x_n-L|$ < $\epsilon$]

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1 Answer

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Your two mathematical sentences are equivalent, so it doesn't matter. (There is a typo in the English version of the second sentence: you meant: "there does not exist".)

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Maya Lin-Takahashi

Maya Lin-Takahashi

Consumer Tech & Gadget Reviewer

Maya is a hardware enthusiast who tests and reviews smart home devices, smartphones, wearables, and audio gear. She focuses on practical consumer value and build quality.

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