The Gateway to Computer Science Excellence
0 votes

Let r1= (a+b2)* ,  r2 = (a* + b*)* , r3 = (a2 + b)*

Which of the following is true?

a)L(r1) is a subset of L(r2) and L(r3) is a subset of L(r2)

b)L(r2) is a subset of L(r1) and L(r2) is a subset of L(r3)

c)L(r1) = L(r3) is a subset of L(r2)

d) L(r1) U L(r3) = L(r2)

in Theory of Computation by Active | 48 views
r2 is (a+b)*. r1 and r2 are not equal to (a+b)* as strings like 'b' and 'a' don't belong to r1 and r2 respectively.

clearly, a is correct!
r2 is (a+b)*

B. not correct r1 cannot generate b and r3 cannot generate a

C. L1 and L3 not equal.

D. L1 or L3 cannot generate ab

So A is correct.

Please log in or register to answer this question.

Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true
52,223 questions
59,816 answers
118,089 users