next event in [$e$;${\it bound}$] after which $x$ = $v$
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$(TERMOF\{next{-}var{-}value:ObjectId, 1:l, i:l\}(${\it es}$,$T$,${\it eq}$,$v$,$x$,$e$,${\it bound}$)).1