{w| w ∈ {a, b} * is not a palindrome} Prove this language is not regular.
86858
Prove that the set of palindromes are not regular languages using the pumping lemma.
35115
Questions on how to prove that a set of connectives is NOT functionally complete
88645
Prove that the additive groups $\mathbb{R}$ and $\mathbb{Q}$ are not isomorphic.
137646
show that language $L'$ is regular (given $L$ regular)
156459
infinite monoid H that is not a free monoid and contains a free monoid as a submonoid
19804
How to prove that $|w_{n+1}-w_n| \leq (2/3)^2 |w_n - w_{n-1}|$?
98963
Prove that neither $A$ nor $B$ is divisible by $5$
32589
Prove or disprove that Arg(zw)=Arg(z)+Arg(w)
146486
Why isn't [ -n ] false like [ -n "" ]?
79056
Prove that $\mathbb Z^n$ is not isomorphic to $\mathbb Z^m$ for $m\neq n$
88982
Prove that for any two sets $A$ and $B$, $A\notin B$ or $B\notin A$
135241
Show that $\mathbb{Z}/n^2\mathbb{Z}$ is not isomorphic to other group
61602
Binary strings (words) proof
22245
Show the union of two subrings is generally not a subring
43927
How to check that a string is a palindrome using regular expressions?
83023
From axiom of regularity, how can I prove $x \notin y \lor y \notin x$
125668
A proof that BS(1,2) is not polycyclic