Problem Detail: It seems that the distinction between fibers and threads is that fibers are cooperatively scheduled, whereas threads are preemptively scheduled. The point of the scheduler seems like a way to make an otherwise serial processor resource act in a Read More …
Author: ignougroup
[Solved]: Is there a repository for the hierarchy of proofs?
Problem Detail: I am self-learning proof assistants and decided to start on some basic proofs and work my way up. Since proofs are based on other proofs and so form a hierarchy, is there a repository of the hierarchy of proofs? Read More …
[Solved]: Concatenation of the intersection of two languages
Problem Detail: I’m enrolled to a Formal Language And Automata course, and we have to prove this equation on sets of strings: $$(L_1cap L_2)cdot L_3 ≠ (L_1cdot L_3) cap (L_2cdot L_3)$$ I’ve tried a lot of sets for e.g. $L1 = Read More …
[Solved]: Are there any specific problems known to be undecidable for reasons other than diagonalization, self-reference, or reducibility?
Problem Detail: Every undecidable problem that I know of falls into one of the following categories: Problems that are undecidable because of diagonalization (indirect self-reference). These problems, like the halting problem, are undecidable because you could use a purported decider for Read More …
[Solved]: What are the k characters which make the most complete words?
Problem Detail: Given a word list of $N$ words formed from a language of $M$ characters, where each word is composed of $n geq 1$ not necessarily distinct characters, how can I find the best set of $k<M$ characters to learn, Read More …
[Solved]: Convert RE to DFA
Problem Detail: I’ve been trying to convert a regular expression to a non-deterministic finite automata (NFA) first using Thompson’s construction, giving: , which looks correct. I am then using subset construction to create the DFA from the NFA, shown here. But Read More …
[Solved]: Is $epsilon$ always contained in $Sigma^*$?
Problem Detail: Please correct me on any terminology. For some reason I’m a bit confused. $Sigma = {epsilon, 0, 1}$ This means my alphabet, $Sigma$, contains three symbols ($epsilon, 0, 1$). $Sigma^*$ is the language over $Sigma$, and it equals ${epsilon, Read More …
[Solved]: counting binary, with moving position (turing machine)
Problem Detail: I’m trying to make a turing machine that will take in a binary string as input x and output the binary representation of the length of x. So M(0110) returns 100, M(1010101010) returns 1010, ect. It also has to Read More …
[Solved]: NP complete language having no Polytime decidable superset
Problem Detail: Is there an NP complete language having no polytime decidable superset (apart from the set of all strings)? Asked By : ARi Answered By : David Richerby No, assuming P$,neq,$NP. Let $L$ be any NP-complete language over alphabet $Sigma$ and let $N Read More …
[Solved]: Is the infinite union of computable sets computable?
Problem Detail: My intuition is telling me that this is untrue. But I am having trouble formulating a proof for this. Can anyone point me in the right direction? I’ve seen a proof by contradiction involving the union of all singletons Read More …
