Author: ignougroup

Problem Detail: The question is in the title, I suppose. I am studying complexity classes, and I understand that NP-Hard is the set of problems that are at least as hard as the hardest problems in NP. Therefore, it will naturally Read More …

Problem Detail: An exercise asks me to show that the Kleene star of any unary language $L$ is regular. $E$ is the alphabet, $E = { 1 }$ Here’s my reasoning : $L$ is regular $implies$ $L^*$ is regular (closure property) Read More …

Problem Detail: I’m looking for some clarification on some concepts/facts I came across while studying for a class. I was reading the following wikipedia article. The below specific section and statement intrigued me when looking it over. http://en.wikipedia.org/wiki/Computational_complexity_theory#Important_complexity_classes “It turns out Read More …

Problem Detail: I just started a course called ‘Automata and Formal Languages’. I’m having difficulty in proofingdisproofing this equality. $ (L_{1} circ L_{2})^{+} = L_{1}^{+} circ L_{2}^{+} $ Where: $ L_{1} $, $L_{2}$ are Languages. $circ$ is the concatenation operation between Read More …

Problem Detail: The problem: Only pattern-like images are supposed to be uploaded and be used as backgrounds to a site, photos should not. How would you detect if an image looks enough like itself to be regarded as a pattern? Asked Read More …

Problem Detail: In other words, what advantages does Hybrid threading have over 1:1 (kernel only) and N:1 (user only) threading? This is a follow-up to What is the difference between user-level threads and kernel-level threads? Asked By : Sheldon Answered By : svick Read More …

Problem Detail: Here is the pseudocode for LSD radix sort from http://www.cs.princeton.edu/~rs/AlgsDS07/18RadixSort.pdf public static void lsd(String[] a) { int N = a.length; int W = a[0].length; for (int d = W-1; d >=0; d–) { int[] count = new int[R]; for(int Read More …

Problem Detail: Consider a square, ABCD. Intuitively it seemed to me that its chromatic polynomial is $lambda(lambda – 1)(lambda – 1)(lambda – 2)$ where there are $lambda$ colours available.. That is there are $lambda$ ways in which a colour for A Read More …

Problem Detail: How can you show that coloring search can be solved by making a polynomial number of calls to the solution for coloring optimization or coloring decision? (Coloring search is the algorithm to color the vertices of a graph such Read More …

Problem Detail: This question occurred to me about the halting problem and I couldn’t find a good answer online, wondering if someone can help. Is it possible that the halting problem is decidable for any TM on any input so long Read More …