Definition:Sufficiently Small

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Let $P$ be a property of real numbers.


$\map P x$ holds for all sufficiently small $x$

if and only if:

$\exists \epsilon \in \R_{>0}: \forall x \in \R: \size x \le \epsilon: \map P x$

That is, if and only if:

There exists a real number $\epsilon$ such that for every (real) number not more than $\epsilon$ in in absolute value, the property $P$ holds.

It is not necessarily the case, for a given property $P$ about which such a statement is made, that the value of $\epsilon$ actually needs to be known, merely that such a value can be demonstrated to exist.

Also see