eclbase?($x$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$ecl\_ind($x$;$k$,${\it test}$.true$_{2}$;$a$,$b$,${\it rec}_{1}$,${\it rec}_{2}$.false$_{2}$;$a$,$b$,${\it rec}_{1}$,${\it rec}_{2}$.false$_{2}$;$a$,$b$,${\it rec}_{1}$,${\it rec}_{2}$.false$_{2}$;$a$,${\it rec}_{1}$.false$_{2}$;$a$,$n$,${\it rec}_{1}$.false$_{2}$;$a$,$n$,${\it rec}_{1}$.false$_{2}$;$a$,$l$,${\it rec}_{1}$.false$_{2}$)