Problem Detail: I have just completed the first chapter of the Introduction to the Theory of Computation by Michael Sipser which explains the basics of finite automata. He defines a regular language as anything that can be described by a finite Read More …
Author: ignougroup
Problem A is polynomially reducible to problem B…what can we say about A and B?
Problem Detail: This is a question on a practice final. Problem A is polynomially reducible to problem B. Which of the following statements is correct? I. If problem A is solvable in a polynomial time then problem B is solvable in Read More …
How can I prove algorithm correctness?
Problem Detail: How can I prove algorithm correctness ? when i face a problem and come up with a solution the only way to know if this a valid solution or not is by trying some test cases. if they pass Read More …
Looking for a dictionary of math/CS notation
Problem Detail: There is an at-times dizzying array of symbols used in math and CS papers. Yet many assume basic familiarity that seems rarely taught in one place. I am looking for a dictionary something like the following, especially from a Read More …
Converting to CFG from a CFL?
Problem Detail: I am trying to learn CFG. Now to make a CFG from a CFL it is really difficult for me. Is there any simple rule or steps so that I can easily find a CFG for a CFL. I Read More …
How does a single-track Turing machine simulate a multi-track Turing machine?
Problem Detail: It’s easy to see how a multi-track Turing machine can simulate a single-track Turing machine; it does so by ignoring all but the first track. But how does it work the other way? I need a specification of a Read More …
How to memorize Master Theorem?
Problem Detail: I know the maths behind, I know if I do the algebra I can get the result of the 3 cases. I also have an intuition of the 3 cases: Quora However, I just cannot memorize this “simple” 3 Read More …
Enumerate all non-isomorphic graphs of a certain size
Problem Detail: I’d like to enumerate all undirected graphs of size $n$, but I only need one instance of each isomorphism class. In other words, I want to enumerate all non-isomorphic (undirected) graphs on $n$ vertices. How can I do this? Read More …
How to prove the NP-completeness of the “Exact-3D-Matching“ problem by reducing the “3-Partition“ problem to it?
Problem Detail: Background: The Exact-3D-Matching problem is defined as follows (The definition is from Jeff’s lecture note: Lecture 29: NP-Hard Problems. You can also refer to 3-dimensional matching): Exact-3D-Matching: Given a set $S$ and a collection of three-element subsets of $S$, Read More …
Halting problem reduction to Halting for all inputs
Problem Detail: I was going through my book of revision and I would like someone hints on this. The Halt for All Input problem (HAI) takes a machine and tell if this machine halts or not for any input We prove Read More …
