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Recent questions tagged regularexpressions
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Stanford slides
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2
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1
Doubt
What is identity for regular expressions ?
asked
Feb 10
in
Theory of Computation
by
Angkit
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3.2k
points)

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regularexpressions
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1
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2
CMI2017A01
The regular expression (a*+b)* is equivalent to which of the following regular expressions: (a) a*b* (b) (a*b+b)* (c) (a+b*)* (d) (a*b)*
asked
Feb 5
in
Theory of Computation
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Tesla!
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theoryofcomputation
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3
Regular expression
S > AaB A > aC  $\epsilon$ B > aB  bB  $\epsilon$ C > aCb  $\epsilon$ Is the regular expression for the above is this: a(a + b)* a ( a* + b* )* ?
asked
Feb 1
in
Theory of Computation
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Tuhin Dutta
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62
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theoryofcomputation
regularexpressions
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3
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4
Regular Expression
Can I write a* + b* = (a + b)* ????
asked
Jan 31
in
Theory of Computation
by
MRINMOY_HALDER
(
161
points)

80
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regularexpressions
theoryofcomputation
identifiers
0
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0
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5
#TOC Doubt
L = anbm / n,m>=1 What type pf Language is this? Also, please tell are n,m are independent or dependent i.e can we have like n=2 and m=3 or both n,m have to have same values!?
asked
Jan 30
in
Theory of Computation
by
iarnav
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20k
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22
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theoryofcomputation
finiteautomata
regularexpressions
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0
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1
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6
Made easy test
(a^n)^m b^n where n>=0 and m>1 is a) regular b) cfl c) csl d) none
asked
Jan 29
in
Theory of Computation
by
♥_Less
Junior
(
989
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52
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madeeasytestseries
regularexpressions
regularlanguages
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contextsensitive
+2
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1
answer
7
Concatenation: REG / REC / DCFL / CFL?
asked
Jan 27
in
Theory of Computation
by
Tuhin Dutta
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51
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theoryofcomputation
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contextfreelanguages
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8
test series rbr
I just want to ask what statement s2 means ?
asked
Jan 12
in
Theory of Computation
by
Moin Mukhtar
(
317
points)

77
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regularexpressions
theoryofcomputation
testseries
+2
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1
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9
regular expressions
Answer is c. but i think it should be b as r1 = (0+1)* = r2=r3. please correct me if i m wrong
asked
Jan 11
in
Theory of Computation
by
amIndian
(
93
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73
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theoryofcomputation
regularexpressions
regularlanguages
finiteautomata
+1
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10
Regular expression
How this last step is done ?
asked
Jan 8
in
Theory of Computation
by
Pawan Kumar 2
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48
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regularexpressions
+1
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11
Regular expressions
asked
Jan 1
in
Theory of Computation
by
Aakanchha
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673
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57
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theoryofcomputation
regularexpressions
regularlanguages
#theoryofcomputation
0
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12
Regular Expression
Let say we have given 10 Regular Expression and we need to check which of them is pointing to the same Regular Language. Then which one of the following is best method Brute Force method (Take some string and cross verify it) Create Minimal dfa for them Using intuition You are trying to observe the language pattern
asked
Dec 23, 2017
in
Theory of Computation
by
hacker16
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2.6k
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62
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regularexpressions
theoryofcomputation
regularlanguages
0
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0
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13
Regular Expression
L1 = (a + b)* b (a+b)* L2 = a* b (a+b)* L3 = (a+b)* ba* Explain L1 = L2 = L3 ?
asked
Dec 23, 2017
in
Theory of Computation
by
hacker16
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2.6k
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64
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theoryofcomputation
regularexpressions
regularlanguages
+1
vote
1
answer
14
Regular Expression
L1 = (0 + 11*0)* L2 = (1*0)* Explain L1 = L2 ?
asked
Dec 23, 2017
in
Theory of Computation
by
hacker16
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2.6k
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75
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theoryofcomputation
regularexpressions
regularlanguages
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0
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15
Regular expression
$(\ 0\ +\ (\ 1\ (\ 0\ 1^*\ 0\ )^*\ 1\ ))^*$ How can the above regular expression produce this string: $1100100011011001011$
asked
Dec 14, 2017
in
Theory of Computation
by
Tuhin Dutta
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theoryofcomputation
regularexpressions
0
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0
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16
Doubt on Regular expression
$a^*\ \ \ and\ \ \ a*$ Isn't the above two same? Let $L\ =\ aa^*,\ then\ L^+\ =\ LL^*\ =\ aa^*(aa^*)^*\ =\ aa^*a*\ =\ aa*$ I couldn't understand the last and the 2nd last step. Please explain.
asked
Dec 14, 2017
in
Theory of Computation
by
Tuhin Dutta
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7.5k
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49
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theoryofcomputation
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0
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1
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17
#TOC DOUBT
Let L be the set of letters {_,A,B,...Z,a,b,…z} and D be the set of digits {0,1…9}. Then which of the following regular expression represents the set of valid C identifiers. Assume that any C keyword is also allowed as variable name. L*(L+D)* LL*D* L(L+D)* None of the above Please explain with valid reason..? Thanks,
asked
Dec 12, 2017
in
Theory of Computation
by
Sahil1994
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1.3k
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theoryofcomputation
regularexpressions
+1
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4
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18
doubt_theory of computation
If L1 = { an  n ≥ 0 } and L2 = { bn  n ≥ 0 }, Consider then L1 . L2 wil be a) (ab)^n b) a^n b^n c) b^n a^n d)b^m a^n e) { a^m b^n  m ≥ 0, n ≥ 0 } why answer is d why noy b ????
asked
Dec 9, 2017
in
Theory of Computation
by
air1ankit
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3.9k
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102
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theoryofcomputation
finiteautomata
regularexpressions
madeeasytestseries
turingmachine
0
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0
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19
self_doubt theory of computation
asked
Dec 8, 2017
in
Theory of Computation
by
air1ankit
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3.9k
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41
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theoryofcomputation
regularexpressions
finiteautomata
turingmachine
0
votes
1
answer
20
[Doubt] Conversion of finite automata to regular expression
asked
Dec 8, 2017
in
Theory of Computation
by
tonystark007
(
133
points)

99
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theoryofcomputation
finiteautomata
nfa
regularexpressions
+1
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1
answer
21
Stanford(Automata Theory)
The operation DM(L) is defined as follows: Throw away every evenlength string from L. For each oddlength string, remove the middle character. For example, if L = {001, 1100, 10101}, then DM(L) = {01, 1001}. That is, evenlength string ... of regular expression ((0+1)(0+1))*. DM(L2) is regular; it is the language of regular expression (0+1)*.
asked
Dec 5, 2017
in
Theory of Computation
by
vijay_jr
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1.2k
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74
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theoryofcomputation
finiteautomata
regularexpressions
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0
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22
Simple doubt in Reg Exp of TOC
why $bb^*$ is $b^*$ and not $b^+$? Ref: $a^*(bb^*a + a)a^*\\=a^*(bb^*+\epsilon)aa^*\\=a^*b^*aa^*\\=a^*b^*a^*a$
asked
Dec 4, 2017
in
Theory of Computation
by
Tuhin Dutta
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7.5k
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66
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theoryofcomputation
regularexpressions
dfa
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0
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23
Regular expression
Infinite intersection of regular set need not be regular. Example please?
asked
Dec 4, 2017
in
Theory of Computation
by
akankshadewangan24
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(
4.7k
points)

33
views
regularexpressions
0
votes
0
answers
24
DFA and Reg Exp
$ L = \{ wxwy \  \ \ x,y,w \ \ \epsilon\ ( a + b )^+ \} $ Draw the DFA and also write the Reg exp for the above language.
asked
Dec 4, 2017
in
Theory of Computation
by
Tuhin Dutta
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7.5k
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108
views
regularexpressions
dfa
theoryofcomputation
+2
votes
2
answers
25
Regular expression for single state FA without final state
asked
Dec 4, 2017
in
Theory of Computation
by
Tuhin Dutta
Boss
(
7.5k
points)

62
views
theoryofcomputation
finiteautomata
regularexpressions
0
votes
1
answer
26
regular expression
asked
Dec 3, 2017
in
Theory of Computation
by
Parshu gate
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6.4k
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45
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regularexpressions
0
votes
0
answers
27
Regular Expression from Finite Automata
asked
Dec 2, 2017
in
Theory of Computation
by
Namit Dhupar
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1.5k
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74
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finiteautomata
theoryofcomputation
expression
regularexpressions
+4
votes
1
answer
28
Stanford(Regular expression)
This DFA accepts a certain language L. In this problem we shall consider certain other languages that are defined by their tails, that is, languages of the form (0+1)*w, for some particular string w of 0's and 1's. Call this language L(w). ... . L(110101) is contained in L. C). L(1111001) is contained in L. D). L(110101) is disjoint from L.
asked
Dec 2, 2017
in
Theory of Computation
by
vijay_jr
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(
1.2k
points)

84
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regularexpressions
theoryofcomputation
regularlanguages
+1
vote
0
answers
29
made easy test series
The language {w the length of w is odd and it's middle symbol is 0, Wε(0+1)*} Why do we need a PDA for above language. I don't think we need a PDA for this language. I wrote the following RE. Tell me whats wrong in it: [(0+ ... )(0+1)]+ + (other small left over strings like 0,101,100,001,000..... which are not covered in first part of expression)
asked
Nov 29, 2017
in
Theory of Computation
by
♥_Less
Junior
(
989
points)

54
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madeeasytestseries
theoryofcomputation
dpda
npda
cfg
regularexpressions
regularlanguages
0
votes
0
answers
30
CFL To Regular Expression
Is there any standard way for converting CFL To Regular Expression assuming CFL represents a regular language? and i need to prove the language L = {w#w  w belongs to {0,1}} to be not a CFL. My approach was: i can take a string say ... # 0^k 1^k as its in the language and i used pumping lemma and proved it to be non CFL is approach correct?
asked
Nov 28, 2017
in
Theory of Computation
by
Na462
Active
(
1.2k
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32
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theoryofcomputation
regularexpressions
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