Search Results
| Search type | Search syntax |
|---|---|
| Tags | [tag] |
| Exact | "words here" |
| Author |
user:1234 user:me (yours) |
| Score |
score:3 (3+) score:0 (none) |
| Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
| Views | views:250 |
| Code | code:"if (foo != bar)" |
| Sections |
title:apples body:"apples oranges" |
| URL | url:"*.example.com" |
| Saves | in:saves |
| Status |
closed:yes duplicate:no migrated:no wiki:no |
| Types |
is:question is:answer |
| Exclude |
-[tag] -apples |
| For more details on advanced search visit our help page | |
Results tagged with regular-languages
Search options not deleted
user 11632
Questions about properties of the class of regular languages and individual languages.
3
votes
4
answers
2k
views
Language where every prefix has almost equal a's and b's
Is the following language regular?
$$L = \{x \in \{a, b\}^* \mid \text{in every prefix \(w\) of \(x\), } 0 \le |w|_a − |w|_b \le 2\}$$
If so, give a DFA for it with as few states as possible. If you …
- 49
0
votes
1
answer
2k
views
Showing Context Free Grammars that are regular if and only if L(G) = Σ∗.
Suppose that G is a context-free grammar. How can I show that “Is L(G) regular?” is undecidable. Also, prove that L is always context-free but is regular if and only if L(G) = Σ∗.
This is what I hav …
- 49
-1
votes
1
answer
149
views
L is a regular language and w is any word, not necessarily in L. Show that L is regular
$L$ is a regular language and $w$ is any word, not necessarily in $L$. We define the set as
$$L/w = \{x \in \Sigma ^* \mid xw \in L\}.$$
Show that $L/w$ is regular.
I'm really struggling with this …
- 49