Problem Detail: I’ve designed a few databases in my time, and on more than one occasion the drive to abstract common elements from specific tables has led me to create generic top-level tables which contain those common elements. For example: Table Read More …
Author: ignougroup
[Solved]: Asymptotic Analysis for two variables?
Problem Detail: How is asymptotic analysis (big o, little o, big theta, big theta etc.) defined for functions with multiple variables? I know that the Wikipedia article has a section on it, but it uses a lot of mathematical notation which Read More …
[Solved]: Is the unsolvability of the N-Body Problem equivalent to the Halting Problem
Problem Detail: There is no general analytic solution to the n-body problem that can produce an analytic function which can be used to give an n-body system’s state at arbitrary time t with exact precision. However, there are some special cases Read More …
[Solved]: Hadoop MapReduce Word Counting Example
Problem Detail: In an example of the application of MapReduce provided by University of Utah, it says that Map() function emits <“hello”, 1> every time it sees hello where the reduce function counts the number of instances “hello” occurs My Read More …
[Solved]: Testing two DFAs generate the same language by trying all strings upto a certain length
Problem Detail: Given the language $EQ_{dfa} =$ ${<A, B> | A$ and $B$ are two DFAs and $L(A) = L(B)$ $}$ Prove that $EQ_{dfa}$ is decidable by testing the two DFAs on all strings upto a certain size. Calculate a size Read More …
[Solved]: Theorem Proofs in Coq
Problem Detail: Background I am learning assistance, Coq, on my own. So far, I have completed reading Yves Bertot’s Coq in a Hurry. Now, my goal is to prove some basic results concerning the natural numbers, culminating with the so-called Read More …
[Solved]: Why can’t we find shortest paths with negative weights by just adding a constant so that all weights are positive?
Problem Detail: I’m currently reading introduction to algorithms and came by Johnson’s algorithm that depends on making sure that all paths are positive. the algo depends on finding a new weight function (w’) that is positive for all edges and keeps Read More …
[Solved]: Formal Languages – Expressive power of Formalisms
Problem Detail: I need help with the following question: Order the following formalisms according to their expressive power: placing A before B means that any language definable by A is definable by B. Also state which, if any, of them are Read More …
[Solved]: Difference between regular expressions: $(0^*1^*)^*$ and $(0+1)^*$
Problem Detail: Can anyone tell me what is the difference between the following regular expressions: $(0^*1^*)^*$ and $(0+1)^*$ ? To me they look like generating the same string. Asked By : Abhishek Anand Answered By : Ran G. The language of both regular Read More …
[Solved]: Chomsky normal form and regular languages
Problem Detail: I’d love your help with the following question: Let $G$ be context free grammar in the Chomksy normal form with $k$ variables. Is the language $B = { w in L(G) : |w| >2^k }$ regular ? What is Read More …
