What is an 'Inherently Ambiguous' Context-Free Language?
A language is inherently ambiguous if no unambiguous CFG exists to generate it (e.g., L = {$a^i$ $b^j$ $c^k$ | $i=j$ or $j=k}$).
In grammar simplification, what is a 'Useless Symbol'?
Useless symbols do not contribute to deriving any valid terminal string from start symbol S and can be safely eliminated.
What is a 'Unit Production' in a CFG?
Unit productions substitute one non-terminal directly with another single non-terminal (A → B).
What language is generated by the CFG rules: S → aSb | $\epsilon$?
S → aSb generates matching pairs of 'a's and 'b's around S, deriving L = { $a^n$ $b^n$ | n $\ge 0 } upon \epsilon termination$.
Is the language L = { $a^n$ $b^n$ $c^n$ | n $\ge 1 } a Context-Free Language$?
$A single pushdown stack cannot compare three independent counts simultaneously, making L = { a^n b^n c^n } non-context-free.$