Solution Found!
Say that a variable A in CFL G is usable if it appears in
Chapter , Problem 4.31(choose chapter or problem)
QUESTION:
Say that a variable A in CFL \(G\) is usable if it appears in some derivation of some string \(w \in G\). Given a CFG \(G\) and a variable \(A\), consider the problem of testing whether \(A\) is usable. Formulate this problem as a language and show that it is decidable.
Questions & Answers
QUESTION:
Say that a variable A in CFL \(G\) is usable if it appears in some derivation of some string \(w \in G\). Given a CFG \(G\) and a variable \(A\), consider the problem of testing whether \(A\) is usable. Formulate this problem as a language and show that it is decidable.
ANSWER:Let L be the language corresponding to the problem of testing whether a variable A in a CFG G is usable.
L = {
L is decidable since it can be checked by an algo