Newbetuts

Let $W\subseteq\omega$ be an infinite c.e. set. Show that there is an infinite $X\subseteq W$ such that $X$ is computable.

A proper general recursive function which grows slower than a primitive recursive function.

Proving that $\Omega = (\lambda x.xx)(\lambda x.xx)$ is not typable in the simply typed lambda calculus

Is there an effective theory which "solves" the halting problem?

Is the group isomorphism problem decidable for abelian groups?

If a problem is $\Sigma^1_1$-hard, it is then not in co-RE?

Is there a dense subset of $\mathbb{R}^2$ with all distances being incommensurable?

Not computable but left computable number

Is there any generalization of the hyperarithmetical hierarchy using the analytical hierarchy to formulas belonging to third-order logic and above?

What's a Turing machine?

Why is it undecidable whether two finite-state transducers are equivalent?

Example of a not recursively enumerable set $A \subseteq \mathbb{N}$

What are "oracle results"?

Show that the question "Is there life beyond earth?" is decidable

Recursive in a $\Sigma^0_2$-singleton implies recursive

Text books on computability

Can you define functions which are not primitive recursive, yet total, in Type Theory? [closed]

New posts in computability

Non-computable function having computable values on a dense set of computable arguments

Does there exist a universal pushdown automaton?

Example of a number that is not the limit of a computable sequence

Let $W\subseteq\omega$ be an infinite c.e. set. Show that there is an infinite $X\subseteq W$ such that $X$ is computable.

A proper general recursive function which grows slower than a primitive recursive function.

Proving that $\Omega = (\lambda x.xx)(\lambda x.xx)$ is not typable in the simply typed lambda calculus

Is there an effective theory which "solves" the halting problem?

Is the group isomorphism problem decidable for abelian groups?

If a problem is $\Sigma^1_1$-hard, it is then not in co-RE?

Is there a dense subset of $\mathbb{R}^2$ with all distances being incommensurable?

Not computable but left computable number

Is there any generalization of the hyperarithmetical hierarchy using the analytical hierarchy to formulas belonging to third-order logic and above?

What's a Turing machine?

Why is it undecidable whether two finite-state transducers are equivalent?

Example of a not recursively enumerable set $A \subseteq \mathbb{N}$

What are "oracle results"?

Show that the question "Is there life beyond earth?" is decidable

Recursive in a $\Sigma^0_2$-singleton implies recursive

Text books on computability

Can you define functions which are not primitive recursive, yet total, in Type Theory? [closed]