for every context free grammer G $=($V$,$ T$,$ P$,$ S$),$ another context$-$free grammer G$1=($V$,$ T$,$ P$1,$ S$)$ can be found with no A$-$ PRODUCTION AND SATISFYING L$($G$1)=$ L$($G$)\backslash \{$A$\}$ true or false