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Problem Detail: I’m using Thompson’s algorithm to convert from a regular expression to a NFA. Is Thompson’s algorithm guaranteed to always output a minimal NFA, i.e., a NFA with the smallest possible number of states? For instance, consider this example. I Read More …
Problem Detail: $A=${$ ⟨M⟩$:$M$ $is$ $a$ $Turing$ $Machine$ } What can be said about $A$ ? Specifically, is $A$ decidable,regular,CFL,CSL? I would say $A$ is decidable since we can write an algorithm to check whether a string is a valid encoding Read More …
Problem Detail: As I understand it NP requires a solution to be verifiable in polynomial time. Can you provide examples of solvable problems not verifiable in polynomial time ? Asked By : user533933 Answered By : Raphael Given input $x = langle M Read More …
Problem Detail: In Haskell, the Monads type class has the bind operator, which is represented by the symbol >>= The type of such operator is: (>>=) :: Monad m => m a -> (a -> m b) -> m b Why Read More …
Problem Detail: Say, I have some permutation or combination formula like this, $$frac{n!}{(n-r)!r!},$$ and I want to $bmod$ the result with some big prime ($10^9+7$ for example). I already tried with modular operation and multiplicative inverse but failed (I don’t quite Read More …
Problem Detail: $$ L = {a^ib^jc^k mid i,j,k > 0 text{ and } i+k>j} $$ I say it’s not regular. Proof by pumping lemma: Find a string $xy^iz$ that is not in $L$ (respecting the constraints). Let $w=x^py^pz^p$. Let $i=2$. $x^p(y^py^p)z^p$ Read More …
Problem Detail: I am solving one of the past exams and I am not certain with my solution to one of the exercises. The exercise is asking to give intuitive meaning to modal $mu$-calculus formula: $$ phi = mu Z. langle Read More …
Problem Detail: I have a set of strings $S$ and I am using the edit-distance (Levenshtein) to measure the distance between all pairs. Is there an algorithm for finding the string $x$ which minimizes the sum of the distances to all Read More …
Problem Detail: I am studying different approaches for the definition of computation with continuous dynamical systems. I have been trying to find a nice introduction to the theory of “State transition systems” but failed to do so. Does anybody know a Read More …
Problem Detail: For example, on x86, we have a set of general registers, each named to the function it carries out. We have an Accumulator, which is a storage for a results of different fixed point operations, we have a Base Read More …
