ISRO CSE 2016 PYQ

By Post's Theorem, if both a language L and its complement $\bar{L}$ are recursively enumerable, then L is recursive (decidable).

Recursive rules aSa and bSb add matching characters to both ends, maintaining odd length.

\(B \rightarrow abc\) is pure terminals (Allowed in regular grammars)
Since all rules perfectly fit the criteria for a left-linear regular grammar, the highest type number it can be assigned is Type 3 .

Balanced binary search trees (e.g., AVL trees, Red-Black trees) guarantee O(log n) access time for symbol table operations.

Recursive descent is a top-down parsing technique that builds the parse tree from the start symbol downward.