| context | $\langle X,d\rangle$ $\dots$ Metric space |
| definiendum | $x\in \text{CauchySeq}(X) $ |
| context | $x\in \text{InfSequence}(X) $ |
| range | $\varepsilon\in \mathbb R,\ \varepsilon>0$ |
| range | $n,m,N\in\mathbb N$ |
| postulate | $\forall\varepsilon.\ \exists N.\ \forall (n,m>N).\ d(x_n,x_m)<\varepsilon$ |
Wikipedia: Cauchy sequence