Try finding languages such that L1⊆L2⊆L3 where L1,L3∉ RE and L2∈ R
85799
Finding languages such that $L_{1} \subseteq L_{2} \subseteq L_{3}$ where $L_{1}, L_{3} \notin \mathbb{R}$, $L_{2} \in \mathbb{R}$
47544
A mathematically mature introduction to Turing Machines and Computability [reference-request]
124315
Drawing automata for languages
123598
Showing the set of DFAs that accept nonempty languages is decidable
98474
Show the existence of a certain subgroup of F2
139177
Ramsey Number Inequality: $R(\underbrace{3,3,...,3,3}_{k+1}) \le (k+1)(R(\underbrace{3,3,...3}_k)-1)+2$
102871
$\langle r\rangle$ maximal $\iff r$ irreducible
156459
infinite monoid H that is not a free monoid and contains a free monoid as a submonoid
137921
Reflexivity, Transitivity, Symmertry of the square of an relation
67490
Restricing domains for universal and existential quantifiers
94203
Examples for almost-semirings without absorbing zero
38840
Tightness and Inner Regularity
41899
Notation for: all subsets of size 2
73869
$\mathcal{C}_1 \subseteq \mathcal{C}_2 \implies \sigma( \mathcal{C}_1) \subseteq \sigma( \mathcal{C}_2) $
153573
Counter Example for the union of any number of compact sets is compact in T2-spaces
127596
Composition of equivalence relations
2142
Finding a set of continuous functions with a certain property 2