Chapter 0: Q23P (page 1)
Show that A is decidable iff .
Short Answer
A is decidable as .
.
/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}
Learning Materials
Features
Discover
Chapter 0: Q23P (page 1)
Show that A is decidable iff .
A is decidable as .
.
All the tools & learning materials you need for study success - in one app.
Get started for free
Myhill–Nerode theorem. Refer to Problem . Let L be a language and let X be a set of strings. Say that X is pairwise distinguishable by L if every two distinct strings in X are distinguishable by L. Define the index of L to be the maximum number of elements in any set that is pair wise distinguishable by L . The index of L may be finite or infinite.
a. Show that if L is recognized by a DFA with k states, L has index at most k.
b. Show that if the index of L is a finite number K , it is recognized by a DFA with k states.
c. Conclude that L is regular iff it has finite index. Moreover, its index is the size of the smallest DFA recognizing it.
Consider the undirected graph where, the set of nodes, is
and, the set of edges, is Draw the graphG. What are the degrees of each node? Indicate a path from node 3 to node 4 on your drawing ofG.
Give a counter example to show that the following construction fails to prove that the class of context-free languages is closed under star. Let A be a CFL that is generated by the CFG . Add the new rule and call the resulting grammar. This grammar is supposed to generate A*.
Let are positive binary integers such that
Show that . (Note that the most obvious algorithm doesn’t run in polynomial time. Hint: Try it first where b is a power of .)
Consider the language B=L(G), where Gis the grammar given in
Exercise 2.13. The pumping lemma for context-free languages, Theorem 2.34,
states the existence of a pumping length p for B . What is the minimum value
of p that works in the pumping lemma? Justify your answer.
What do you think about this solution?
We value your feedback to improve our textbook solutions.