Which of the following statements are true?
$$1.$$ Every left-recursive grammar can be converted to a right-recursive grammar and vice-versa
$$2.$$ All ε-productions can be removed from any context-free grammar by suitable transformations
$$3.$$ The language generated by a context-free grammar all of whose productions are of the form $$X \to w$$ or $$X \to wY$$ (where, $$w$$ is a string of terminals and $$Y$$ is a non terminal), is always regular
$$4.$$ The derivation trees of strings generated by a context-free grammar in Chomsky Normal Form are always binary trees

If $$L$$ and $$\overline L $$ are recursively enumerable then $$L$$ is

Which of the following is true for the language $$\left\{ {{a^p}} \right.\left| P \right.$$ prime $$\left. \, \right\}$$?

Match the following List-$${\rm I}$$ with List - $${\rm II}$$

List-$${\rm I}$$
$$E)$$ Checking that identifiers are declared before their
$$F)$$ Number of formal parameters in the declaration of a function agrees with the number of actual parameters in a use of that function
$$G)$$ Arithmetic expression with matched pairs of parentheses
$$H)$$ Palindromes

List-$${\rm II}$$
$$P)$$ $$L = \left\{ {{a^n}{b^m}{c^n}{d^m}\,|\,n \ge 1,m \ge 1} \right\}$$
$$Q)$$ $$X \to XbX\,|\,XcX\,|\,dXf\,|g$$
$$R)$$ $$L = \left\{ {www\,|\,w \in \left( {a\,|\,b} \right){}^ * } \right\}$$
$$S)$$ $$X \to bXB\,|\,cXc\,|\,\varepsilon $$