Adjacent pair in a linear order
= Adjacent pair in a linear order
{title2=$u<v\ \land\ \neg\exists w\,(u<w<v)$}
Two elements $u<v$ of a <totally ordered set> form an adjacent pair when no domain element lies strictly between them. Every pair of consecutive <integers> is adjacent, while a <dense order> has no adjacent pair. A gap in a subset of the <real numbers> matters here only through which points belong to the domain: $1,2$ are adjacent in $[0,1]\cup[2,3]$.