Using the pumping lemma to deduce that the language consisting of palindromes is not regular
126020
pumping lemma: ww^R not regular
141895
Proving that a sequence is monotone
150385
The use of the Axiom of Choice in this proof of the sequence lemma
104626
Undecidable language problems.
54742
Ukkonen's suffix tree algorithm in plain English
137646
show that language $L'$ is regular (given $L$ regular)
748
What do 'lazy' and 'greedy' mean in the context of regular expressions?
102490
Does this recursive sequence have a closed-form?
130415
Negating quantifiers with brackets
10519
Describe in English a Turing machine that semidecides the following language - Is this solution correct?
135066
How do the authors deduce this weaker version of Transfinite Recursion?
139170
Syntactic characterisation of the intersection of CTL and LTL
47544
A mathematically mature introduction to Turing Machines and Computability [reference-request]
50993
Faithful representations and character tables
25874
Showing that a certain map is not flat by explicit counterexample
113342
Confusion of the decidability of $(N,s)$
22298
Categorical Pasting Lemma