Category: Uncategorized

Problem Detail: Is the language $$L = {a,b}^* setminus {(a^nb^n)^nmid n geq1 }$$ context-free? I believe that the answer is that it is not a CFL, but I can’t prove it by Ogden’s lemma or Pumping lemma. Asked By : Andrés Felipe Read More …

Problem Detail: A source provides a stream of items $x_1, x_2,dots$ . At each step $n$ we want to save a random sample $S_n subseteq { (x_i, i)|1 le i le n}$ of size $k$, i.e. $S_n$ should be a uniformly Read More …

Problem Detail: Are there any “natural” examples of decidable problems that are definitively known not to be in NP? The decidable languages I know of that are not contained in NP are usually derived from the time hierarchy theorem, which produces Read More …

Problem Detail: I consider Point Location Problem in Polygon in repetitive mode in the case of simple polygon. In computational geometry,Point Location Problem in Polygon problem asks whether a given point in the plane lies inside, outside, or on the boundary Read More …

Problem Detail: A YouTube video I was watching explained the differences between Imperative and Functional programming by demonstrating how the numbers from 1 to 10 are summed up in Java and in Haskell respectively. In Java, you must explicitly state each Read More …

Problem Detail: $S rightarrow S$, $L(G) = {}$ LL(1) analysis: We estabilish $FIRST(S)$ to be empty and $FOLLOW(S)$ to be ${$}$. $FIRST(S)$ doesn’t contain ε, so the parse table looks like this: +—+—+ | | $ | +—+—+ | S | Read More …

Problem Detail: I know that the complexity class $mathsf{P}$ has complete problems w.r.t. $mathsf{NC}$ and $mathsf{L}$ reductions. Are these two classes the only possible classes of reductions under which $mathsf{P}$ has complete problems? Also, what classes of reduction can be used Read More …