What is this grammar? Context-free or context sensitive...

regular expression with matching empty string...

HTML Input field pattern for numerical values....

Is this a regular language? If so, what is it's regular expression?...

non-unicode use regex pattern less few letters...

Can someone help me with this proof using the pumping lemma?...

Regular Expressions - Repeating Pattern...

formal languages: what does R-trivial mean?...

Regular expression to filter urls with strings repeated 3 times or more...

Aren't modern regular expression dialects regular?...

Regular Expression for matching keywords in different styles of URL's...

What is the intersection of two languages with different alphabets?...

simplify regex, [star] mysteriously disappears...

How to extract the words from the tree structure using Regex pattern...

How to write factorial function using the L language?...

Is this a free context gramar language?...

Deciding if a given Language is Regular/Context-Free/Non Context-Free...

How to solve δ(A,01) for this DFA?...

Techniques for simplifying a regular expression **by hand**...

Given a sequence of symbols, how to find the minimal DFA that can accept it?...

Pumping Lemma, Condition 1...

Is it possible to simplify this regular expression any further?...

How do I find the language from a regular expression?...

How would I convert regular expression to finite automata?...

Find a regular expression for strings containing the substring 01a and even number of 1's over t...

Can one find out which input characters matched which part of a regex?...

how can i see directly that a language is not regular...

regular expressions for url parser...

Regular Expression in Perl to check fit/match...

Exclude part of the string with regex...