Question 5 of Assignment 1, Semester 1 reads currently as follows:
S -> aX | Yb
X -> ZXYZ
Y -> b | bY | "" (Empty string)
Z -> a | "" (Empty string)
Non-terminal X is useless. This is unfortunately incorrect. To correct this error you should please add the production:
X -> a
Thus the CFG to be converted to CNF should be as follows:
S -> aX | Yb
X -> ZXYZ | a
Y -> b | bY |"" (Empty string)
Z -> a | "" (Empty string)
My apologies for the error in your TL101. Note that we shall comment on Question 5 but that we shall not allocate marks to Question 5.
Kind regards
C de Ridder