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Problem Detail: I have to prove that $left { a, b right }^{ast} – left { a^ib^i | igeq 0 right }$ is a context-free language and it’s not regular. So far I’ve got that this language is not regular because Read More …

Problem Detail: How do you prove that the language of even-lengthed palindromes, i.e., $L=left{ ww^R mid win leftlbrace 0,1 right}^* right}$, can not be accepted by a determinsitc Push-Down-Automaton? Is there any general way to prove that a context-free language can Read More …

Problem Detail: Clique problem is a well known $NP$-complete problem where the size of the required clique is part of the input. However, k-clique problem has a trivial polynomial time algorithm ($O(n^k)$ when $k$ is constant). I’m interested in the best Read More …

Problem Detail: I am interested in simulating any turing machine with a turing machine that is allowed only to move right. I guess that it should be pretty standard material and likely it is trivial (or known to be false). Does Read More …

Problem Detail: I have been reading about Dijkstra’s algorithm and I think I understand it. I followed the algorithm in pseudo-code from Wikipedia, and now I wonder: If my graph is bi-directional and I add each edge to my graph twice Read More …

Problem Detail: An hypervisor (1st type) is a software that creates and run virtual machines, managing guest’s operative systems’s requests to the hardware. An exokernel is an operative system kernel, that let’s programs access directly to the hardware or, with the Read More …

Problem Detail: When dealing with the analysis of time and space complexity of algorithms, is it safe to assume that any function which has tight bounds ( i.e. $f(n)=Theta(g(n))$ is asymptotically positive and asymptotically monotonically increasing. I mean that for all Read More …

Problem Detail: Could anyone please explain Cantor’s diagonalization principle in simple terms? Asked By : user5507 Answered By : William Macrae Here’s the standard application explained in the simplest terms I can: Theorem: There are more real numbers than there are integers. Lemma: Read More …

Problem Detail: Earlier I asked the question: Can a Turing Machine decide if an NFA accepts a string of prime length?. The answer introduced me to Parikh’s theorem, which I’ve been reading about. The concept of Parikh’s theorem, if we apply Read More …

Problem Detail: How can one calculate the winding number of a polygon given as a list of vertices in some (counter-clockwise or clockwise) order? The complexity of the algorithm must be linear time. Asked By : Dib Answered By : ZeroUltimax The winding Read More …