Blog

Problem Detail: I was looking at the construction proof showing the equivalence of NFA and DFA from Sipser’s text. It started by taking number of states of DFA as $mathcal{P}(Q)$, where $mathcal{P}(Q)$ is the set of subsets of $Q$. My doubt Read More …

Problem Detail: First and foremost, i know what a shell, kernel is. Now the dilemma. Today i had my systems viva in college. The examiner asked me is there a shell between the hardware and the kernel. Obviously, i said no, Read More …

Problem Detail: Given some unrecognizable language $L$, is it possible for its complement $overline{L}$ to also be unrecognizable? If some other language $S$ and its complement $overline{S}$ are both recognizable, then $S$ and $overline{S}$ are decidable. If $overline{S}$ is unrecognizable, then Read More …

Problem Detail: In thinking about how to approach this problem I think several things will be required, some tivial: An expression tree where non-leaf node is an operation (not sure if that part is redundant), but not every node has just Read More …

Problem Detail: I’ve heard the motto interaction is more powerful than algorithms from Peter Wegner. The basis of the idea is that a (classical) Turing Machine cannot handle interaction, that is, communication (input/output) with the outside world/environment. How can this be Read More …

Problem Detail: This might border on computational cognitive science, but I am curious as to how the process followed by common pathfinding algorithms (such as A*) compares to the process humans use in different pathfinding situations (given the same information). Are Read More …

Problem Detail: I can not understand why the dynamic programming algorithm for the Subset Sum, is not polynomial. Even though the sum to find ‘T’ is greater than the total sum of the ‘n’ elements of the set , the number Read More …

Problem Detail: My question is basically given three languages A, B and L, where L is A and B concatenated together and B is proven to be non regular, is it possible to find an A that makes L regular? Asked Read More …

Problem Detail: I am trying to understand why the modular exponentiation algorithm has a running time of about $log(n)$ where $n$ is the exponent. Here is the algorithm: function modular_pow(base, exponent, modulus) result := 1 while exponent > 0 if (exponent Read More …

Problem Detail: If I am given a graph which forms a tree, I am interested in finding a vertex which maximizes the minimum distance to any leaf. I am sure this problem has been studied before. Does anybody know the name Read More …