If the string of L consists of 0's only prove that L* is regular Unicorn Meta Zoo #1: Why another podcast? Announcing the arrival of Valued Associate #679: Cesar Manara Data science time! April 2019 and salary with experience The Ask Question Wizard is Live!Regular expression to match string of 0's and 1's without '011' substringProving a Language to be regularWhat regular language intersects with 1*0* gives 1n0nUsing Closure Properties to prove RegularityProving Regular LanguagesProving that a language is regularDesign a regular expression or Finite Automata for a language that consists of 01 or 010?Prove that a context-free-grammar is regularRegular languages and pumping lemma1 or 2 right hand side variable in Context free language
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If the string of L consists of 0's only prove that L* is regular
Unicorn Meta Zoo #1: Why another podcast?
Announcing the arrival of Valued Associate #679: Cesar Manara
Data science time! April 2019 and salary with experience
The Ask Question Wizard is Live!Regular expression to match string of 0's and 1's without '011' substringProving a Language to be regularWhat regular language intersects with 1*0* gives 1n0nUsing Closure Properties to prove RegularityProving Regular LanguagesProving that a language is regularDesign a regular expression or Finite Automata for a language that consists of 01 or 010?Prove that a context-free-grammar is regularRegular languages and pumping lemma1 or 2 right hand side variable in Context free language
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A question 4.2.10 from Introduction to Automata Theory by Hopcroft and Ullman. The original language L can also be non-regular.
Let's say we got a function of 0^(2^n+5), n>=0, how would you prove that (0^(2^n+5))* is regular? And also for the more general case, when f(0) can be any function?
regular-language automata
add a comment |
A question 4.2.10 from Introduction to Automata Theory by Hopcroft and Ullman. The original language L can also be non-regular.
Let's say we got a function of 0^(2^n+5), n>=0, how would you prove that (0^(2^n+5))* is regular? And also for the more general case, when f(0) can be any function?
regular-language automata
add a comment |
A question 4.2.10 from Introduction to Automata Theory by Hopcroft and Ullman. The original language L can also be non-regular.
Let's say we got a function of 0^(2^n+5), n>=0, how would you prove that (0^(2^n+5))* is regular? And also for the more general case, when f(0) can be any function?
regular-language automata
A question 4.2.10 from Introduction to Automata Theory by Hopcroft and Ullman. The original language L can also be non-regular.
Let's say we got a function of 0^(2^n+5), n>=0, how would you prove that (0^(2^n+5))* is regular? And also for the more general case, when f(0) can be any function?
regular-language automata
regular-language automata
asked Mar 22 at 13:42
VladimirVladimir
83
83
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Suppose that L contains two strings 0^n and 0^m and that n and m share no common factors: they are relatively prime. Then, by concatenating some number of instances of 0^n with some number of instances of 0^m, any string of length (n - 1)(m - 1) can be formed. Since L* must therefore exclude only a finite number of words, the complement (L*)' must be finite, hence regular; because regular languages are closed under complement, L* must be regular too.
Where did (n - 1)(m - 1) come from? Well, it's a special case (n = 2) of the coin problem for which we have a closed-form solution. You should be able to research this and find some proofs.
What about the case where all strings in L have lengths divisible by some GCD, say g? Well, the proof of regularity is quite similar; consider a modified alphabet where 0 is replaced by the symbol (0^g) and then prove the analogous language over this alphabet is regular as above. In other words, you can show that L* contains only strings divisible by g and all strings divisible by g of length at least (n/g - 1)(m/g - 1) where n and m have GCD g. The language is regular because it excludes only finitely many words whose lengths are divisible by g.
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Suppose that L contains two strings 0^n and 0^m and that n and m share no common factors: they are relatively prime. Then, by concatenating some number of instances of 0^n with some number of instances of 0^m, any string of length (n - 1)(m - 1) can be formed. Since L* must therefore exclude only a finite number of words, the complement (L*)' must be finite, hence regular; because regular languages are closed under complement, L* must be regular too.
Where did (n - 1)(m - 1) come from? Well, it's a special case (n = 2) of the coin problem for which we have a closed-form solution. You should be able to research this and find some proofs.
What about the case where all strings in L have lengths divisible by some GCD, say g? Well, the proof of regularity is quite similar; consider a modified alphabet where 0 is replaced by the symbol (0^g) and then prove the analogous language over this alphabet is regular as above. In other words, you can show that L* contains only strings divisible by g and all strings divisible by g of length at least (n/g - 1)(m/g - 1) where n and m have GCD g. The language is regular because it excludes only finitely many words whose lengths are divisible by g.
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Suppose that L contains two strings 0^n and 0^m and that n and m share no common factors: they are relatively prime. Then, by concatenating some number of instances of 0^n with some number of instances of 0^m, any string of length (n - 1)(m - 1) can be formed. Since L* must therefore exclude only a finite number of words, the complement (L*)' must be finite, hence regular; because regular languages are closed under complement, L* must be regular too.
Where did (n - 1)(m - 1) come from? Well, it's a special case (n = 2) of the coin problem for which we have a closed-form solution. You should be able to research this and find some proofs.
What about the case where all strings in L have lengths divisible by some GCD, say g? Well, the proof of regularity is quite similar; consider a modified alphabet where 0 is replaced by the symbol (0^g) and then prove the analogous language over this alphabet is regular as above. In other words, you can show that L* contains only strings divisible by g and all strings divisible by g of length at least (n/g - 1)(m/g - 1) where n and m have GCD g. The language is regular because it excludes only finitely many words whose lengths are divisible by g.
add a comment |
Suppose that L contains two strings 0^n and 0^m and that n and m share no common factors: they are relatively prime. Then, by concatenating some number of instances of 0^n with some number of instances of 0^m, any string of length (n - 1)(m - 1) can be formed. Since L* must therefore exclude only a finite number of words, the complement (L*)' must be finite, hence regular; because regular languages are closed under complement, L* must be regular too.
Where did (n - 1)(m - 1) come from? Well, it's a special case (n = 2) of the coin problem for which we have a closed-form solution. You should be able to research this and find some proofs.
What about the case where all strings in L have lengths divisible by some GCD, say g? Well, the proof of regularity is quite similar; consider a modified alphabet where 0 is replaced by the symbol (0^g) and then prove the analogous language over this alphabet is regular as above. In other words, you can show that L* contains only strings divisible by g and all strings divisible by g of length at least (n/g - 1)(m/g - 1) where n and m have GCD g. The language is regular because it excludes only finitely many words whose lengths are divisible by g.
Suppose that L contains two strings 0^n and 0^m and that n and m share no common factors: they are relatively prime. Then, by concatenating some number of instances of 0^n with some number of instances of 0^m, any string of length (n - 1)(m - 1) can be formed. Since L* must therefore exclude only a finite number of words, the complement (L*)' must be finite, hence regular; because regular languages are closed under complement, L* must be regular too.
Where did (n - 1)(m - 1) come from? Well, it's a special case (n = 2) of the coin problem for which we have a closed-form solution. You should be able to research this and find some proofs.
What about the case where all strings in L have lengths divisible by some GCD, say g? Well, the proof of regularity is quite similar; consider a modified alphabet where 0 is replaced by the symbol (0^g) and then prove the analogous language over this alphabet is regular as above. In other words, you can show that L* contains only strings divisible by g and all strings divisible by g of length at least (n/g - 1)(m/g - 1) where n and m have GCD g. The language is regular because it excludes only finitely many words whose lengths are divisible by g.
answered Mar 22 at 14:51
Patrick87Patrick87
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