CSC 456/656 Assignment 4
Due date, October 16, 2003, 4:00 PM.
All assignments must be handwritten
(not typed or printed from a computer file)
in your own handwriting, on 8.5 by 11 inch paper. Write your name on
each sheet, and do not fold the pages or crimp the corners.
Turn the pages in to me or to the graduate assistant on the due date.
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Work Exercise 2.14 on page 121 of your textbook.
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Work Exercise 2.17 on page 121 of your textbook, but do not turn it in.
Hint: use the theorem that a language is context-free if and only if it
is accepted by some PDA.
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Show that the set of regular expressions over the binary alphabet
is a context-free language.
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Consider the language ADD in Problem 1 of Assignment 2.
Show that ADD satisfies the conditions of the pumping lemma for
context-free languages.
- Work problem 2.18(a) on page 121 of your textbook.
- Work problem 2.27 on page 122 of your textbook. (This problem
is harder than the others.)
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Let Sigma be the alphabet {a,b,c,d}. Let L be the language consisting
of all strings over Sigma of the form
anbncndn.
Thus, the empty string, abcd, aabbccdd, aaabbbcccddd, ... are in L.
Give a general grammar which generates L. (No credit will be given if
we cannot verify that your grammar is correct with a reasonable amount of
effort.)
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Work problem 3.2 on page 147 of your textbook.
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