User user6530

9 votes

Proof that no O(n) multiplication algorithm exists

answered Jun 4, 2020 at 10:55

7 votes

Accepted

Show $L = $ { w $\in (a,b) ^* $| for every u substring of w, $-5\le|u|_a−|u|_b\le5\}$ is regular

answered Aug 22, 2020 at 13:56

5 votes

Accepted

Proof that L^2 is regular => L is regular

answered Aug 24, 2020 at 22:20

5 votes

CFG that generates $1^*$ is decidable

answered Jul 10, 2020 at 14:33

4 votes

Turing machine for $0^{3^k} 1^{p}$

answered Apr 17, 2021 at 12:16

4 votes

Accepted

pumping lemma, concatenation of non-regular languages $a \neq b$

answered Apr 22 at 22:08

3 votes

Accepted

Is X+Y sorting problem still an open problem?

answered May 30, 2020 at 21:06

3 votes

Accepted

Proof of $f(n) + ο(f(n)) = \Theta(f(n))$

answered Apr 17, 2021 at 18:55

2 votes

Time complexity of $L=\{a^nb^n | n \ge 1\}$

answered Apr 25, 2021 at 15:10

2 votes

Existence / non-existence of a sequence with short longest increasing subsequence and decreasing subsequence?

answered Jul 11, 2020 at 17:37

2 votes

Accepted

Generate the context free grammar for the following language: $\left \{ a^{3n}b^{m}c^{n}|n>0, m>0\right \}$

answered Nov 19, 2020 at 16:50

2 votes

Accepted

Regular languages: words from A that do not contain any word from B as a substring

answered Apr 20 at 16:49

2 votes

Accepted

Describing the Language of a DFA with 7 States

answered Aug 27, 2022 at 9:39

1 vote

Accepted

Recurrence relations and induction: guessing the right bound

answered Nov 20, 2020 at 17:01

1 vote

Accepted

The intersection of 2 CFL

answered Aug 20, 2020 at 12:21

1 vote

Accepted

How can I prove that LTL formula is valid?

answered Jun 8, 2022 at 15:12

1 vote

Comparisons of functions, their big-oh and their implications

answered Apr 17, 2021 at 15:50

1 vote

How does squaring time complexity imply the same time complexity for multiplying different numbers? Isn't it the other way round?

answered Apr 17, 2021 at 16:08

1 vote

Write a CFG for the language $\{0^n 1^a 2^b \mid n = a+b\}$

answered Dec 14, 2020 at 23:36

1 vote

Finding a grammar for $L = \{ 0^x1^y0^z1^w | x+w=y+z\}$

answered Jan 10, 2021 at 19:23

0 votes

Accepted

Grammar for $\{ (n_a(w) - n_b(w)) mod\ 3 = 2 \} $

answered Apr 20, 2021 at 14:23

0 votes

Difference between a regular and a non-regular language

answered Dec 5, 2020 at 21:32

0 votes

Description logics with decision problems within NP

answered Aug 25, 2020 at 19:53

0 votes

Accepted

TMs can decide whether or not a string is a Palindrome, yet, the language called PALINDROMES is undecidable - why?

answered Jul 7, 2023 at 11:21

0 votes

Searching for small finite state automata

answered Apr 19 at 20:43

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25 Answers

Proof that no O(n) multiplication algorithm exists

Show $L = $ { w $\in (a,b) ^* $| for every u substring of w, $-5\le|u|_a−|u|_b\le5\}$ is regular

Proof that L^2 is regular => L is regular

CFG that generates $1^*$ is decidable

Turing machine for $0^{3^k} 1^{p}$

pumping lemma, concatenation of non-regular languages $a \neq b$

Is X+Y sorting problem still an open problem?

Proof of $f(n) + ο(f(n)) = \Theta(f(n))$

Time complexity of $L=\{a^nb^n | n \ge 1\}$

Existence / non-existence of a sequence with short longest increasing subsequence and decreasing subsequence?

Generate the context free grammar for the following language: $\left \{ a^{3n}b^{m}c^{n}|n>0, m>0\right \}$

Regular languages: words from A that do not contain any word from B as a substring

Describing the Language of a DFA with 7 States

Recurrence relations and induction: guessing the right bound

The intersection of 2 CFL

How can I prove that LTL formula is valid?

Comparisons of functions, their big-oh and their implications

How does squaring time complexity imply the same time complexity for multiplying different numbers? Isn't it the other way round?

Write a CFG for the language $\{0^n 1^a 2^b \mid n = a+b\}$

Finding a grammar for $L = \{ 0^x1^y0^z1^w | x+w=y+z\}$

Grammar for $\{ (n_a(w) - n_b(w)) mod\ 3 = 2 \} $

Difference between a regular and a non-regular language

Description logics with decision problems within NP

TMs can decide whether or not a string is a Palindrome, yet, the language called PALINDROMES is undecidable - why?

Searching for small finite state automata