glues(${\it es}$; $B$; $g$; $f$; ${\it Ia}$; ${\it Ib}$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$Q{-}R{-}glues(${\it es}$;$B$;$g$;$f$;${\it Ia}$;$\lambda$$e$,${\it e'}$. es{-}le(${\it es}$;$e$;${\it e'}$);${\it Ib}$;$\lambda$$e$,${\it e'}$. es{-}le(${\it es}$;$e$;${\it e'}$))